Toxins (Poisons) That Effect Dogs


Foods to Avoid Feeding Your Pet

- Alcoholic beverages
- Avocado
- Chocolate (all forms)
- Coffee (all forms)
- Fatty foods
- Macadamia nuts
- Moldy or spoiled foods
- Onions, onion powder
- Raisins and grapes
- Salt
- Yeast dough
- Garlic
- Products sweetened with xylitol

This list is based on the Animal Poison Controls list of death and illness in pets

Sugarless Candies Can Be Toxic to Pets

Sugarless candies can be toxic to pets. Candies containing xylitol have been recognized by the National Animal Poison Control Center to be a risk to pets. This information was first published in July 2004. This compound can cause liver damage and death in dogs susceptible to being poisoned with xylitol. If your dog ingests sugarless candy it would be best to contact the NAPCC (1-888-426-4435). It is possible your vet will not be familiar with this source of poisoning as this information is fairly new and candies have not usually been associated with poisonings in dogs if they did not contain chocolate as the major ingredient.

Dr Mike Richards, DVM


Salmon (Raw) Poisoning Disease

This is primarily a problem in the Pacific Northwest and California. But if you feed a raw meat diet it can be a problem anywhere.

It is caused from the infection by a  rickettsial organism, Neorickettsia helminthoeca. SPD has been known since the early 19th century in North America. It had been observed that dogs that ate raw salmon frequently died however the connection between the fluke and the rickettsia was not established at this time.(1) It is unusual in that the rickettsial organism does not directly infect the dog but is instead carried by a parasite, a trematode (flatworm or fluke) called Nanophyteus salmincola through two intermediate hosts first: freshwater snails and salmonid fish (salmon, trout and steelhead). Nanophyteus salmincola are found to infect freshwater snails particularly Oxytrema plicifer. The infected snail forms part of the salmonid species food web and is ingested. Neither the fluke nor the rickettsial organism act as pathogens in the fish. The dog is exposed only when it ingests the secondary host - an infected fish. After the dog ingests the fish, the encysted fluke larvae burst and embed in the dog’s intestinal tract and the rickettsia are introduced. The cycle continues when ova are excreted in dog feces to infect snails. It is necessary for your dog to eat raw salmon to get salmon poisoning disease.

A sudden onset of symptoms occur 5-7 days after ingestion of fish. Initial symptoms include lethargy and anorexia. Peaking of temperature between 104-107 in the first two days and then slowly returns to normal. Persistent vomiting by the fourth day. There is bloody diarrhea within a few days of vomiting onset. The diarrhea is often bright yellow color. There are enlarged lymph nodes. In the acute stages, gastrointestinal symptoms are quite similar to canine parvovirus. Nasal and ocular symptoms can resemble canine distemper. If left untreated, SPD has a mortality rate of up to 90%. Treatment is supportive to maintain hydration as well as antibiotic therapy to kill the disease producing organism. Dogs that survive are immune. It is preventable by cooking all fish before feeding your dog. If you are outdoors hiking or camping or live near streams and rivers were salmon spawn, keep a close eye on your dog on don't let your pet run free to insure that no fish carcasses are ingested. Please see your vet immediately if you suspect your dog has ingested raw salmon.


Holiday Toxic Brew - Raisin and Alcohol Toxicity

Be Careful of Holiday Toxins and Dangers

This is the time of year when pets can be exposed inadvertently to toxic substances or tempting taste treats that can be dangerous. One "toxic" plant you don't have to worry much about is the poinsettia, though. These plants are either nontoxic or only slightly irritating to the gastrointestinal tract, depending on the reference source. On the other hand, mistletoe berries are poisonous and it is best to be very careful when hanging mistletoe so that pets are not exposed to the berries. Even one or two berries of this plant may be fatal. Even the products used to help plants make it through the holidays can be a problem. Some of the solutions used to make the Christmas tree last through a long holiday season can be pretty irritating to mouth or stomach tissues. If you add these to the water in your Christmas tree stand you should be sure that pets can not drink the water.

Plants are not the only problems. Holiday food treats and decorations can be dangerous to pets. It takes a fairly large amount of milk chocolate to cause poisoning problems in dogs and cats but a whole box of chocolates is likely to cause diarrhea at the least and may be toxic to smaller pets. Tinsel strands seem to be very attractive to cats and these will often cause severe problems, often requiring surgical removal to prevent the death of the cat if they are ingested. For some reason, almost every season a dog or cat in our practice eats a Christmas tree ornament or even one of the light bulbs off the tree. Chewing on the extension cords to the tree lights or the electric train around the tree sometimes leads to problems, too. The abundance of food found at holiday tables presents a danger even if it isn't cooked by your mother-in-law who believes in partially thawing the turkey then cooking it a 200 degrees. We see a definite increase in pancreatitis around the holidays due to pets getting fat laden table scraps. At least one dog a year manages to eat the whole turkey carcass and has a major case of constipation in a day or so. Try to resist the urge to cover the pet's food with the extra gravy and put the trash out of reach of pets after an attractive meal!

Pets sometimes have a really hard time adjusting to the increases in family activity around the holidays. They may not handle the stress of house guests well. Often just scheduling a few minutes at approximately the same time each day to spend playing with your dog or reviewing those obedience exercises can make the holidays a lot easier for an anxious canine. Cats are a little harder to reassure and it is sometimes best just to make sure they have a safe haven in the house where the guests can't find them, especially the very young guests. Make sure their litter pan is private, too.

If you are going to board your pet for the holidays make sure their vaccinations are current well before the time for boarding and check to see if there are special vaccination requirements at the boarding kennel, such as requiring Bordetella (kennel cough) vaccination. Make sure you have all the contact numbers for wherever you will be written down for the kennel, pet sitter or veterinary hospital. You might even consider giving your vet written permission to treat your pets in your absence, especially if your relationship with your vet is not close enough to be sure he or she would be comfortable caring for the pets without your permission. Do not tranquilize pets for air travel if you are taking them with you, unless you are absolutely certain it is necessary. A recent review of pet deaths during airplane trips revealed that most of the pets who died had been sedated. The effects of sedatives are intensified at higher altitudes and even though cargo holds are pressurized they are at a lower atmospheric pressure than is found at ground level. If you do have to sedate a pet follow the veterinarian's directions EXACTLY. It could save your pet's life!

If you take a little time to prepare and think about the special risks holidays impose your pet should be safe. Just in case, make sure you know the number of the emergency veterinary hospitals in your are and can drive by it to be sure you can find it an emergency when you may not be thinking as clearly as on an ordinary day.

Michael Richards, DVM

One of our readers nearly lost both of her Labs to the sediment of a neighbors holiday brew. He thought he would share a treat with them.
They ingested 8 teaspoons each.  (Some fell on the ground, the spoon was a bit heaped)   This was in the form of pulp.
The mixture is as follows:  raisins, oranges, sugar, wine yeast and water. the pulp was in the bottom of the container which had fermented for 5 days. "Pretty Strong Stuff".
Her vet stated:  They both had alcohol toxicity and raisin toxicity.
The 9 year old lab had sampled  this mixture approximately a week before sharing the second ingestion with the readers 18 month old lab.  This time it was intensive care for both dogs.
While both dogs survived their ordeal, the older lab has suffered permanent kidney damage.



Onion and Garlic Toxicity  in Dogs And Cats

Q: Dr. Richard's,   Thank you for your help with past questions and creating this web site.   I have a question about onions and dogs. I read somewhere onions are   poisonous for dogs yet onions are often ingredients in dog treats. Is it just   raw onions that are so dangerous? What about meat that has been cooked with   onions is this dangerous?   What are some things that are toxic for dogs besides chocolate and onions?   Also I own several cats are there foods toxic to them as well?

A:  Kim-

Dogs develop hemolytic anemia if they eat enough onions. I don't think that it matters too much whether the onions are cooked or not. The quantity of onions required is high enough that dogs can generally tolerate small doses of onions without any problem and moderate amounts of onion without clinically apparent disease, even though there may be measurable changes on lab test results. Cats are probably a little more sensitive to onion toxicity than dogs are. I can't find an exact quantity of onions required to cause toxicity problems  in dogs,  but there are several case reports of onion toxicity and they involve whole onions or sizable portions of chopped onions (like a cup or more).  I think that feeding dogs meat that has been cooked with onions is pretty safe but you might want to avoid giving them the broth from around something like pot-roast if there were a lot of onions used in the cooking, just to be safe.

Large amounts of garlic will produce similar toxicity problems in both dogs and cats. I think that the amount required is not likely to be eaten by a cat but there are probably a few dogs who would lap up a container of spilled garlic.

Among common foods, the only other significant toxicity that I can think of are recent reports of toxicity from eating grapes and raisins that have been reported in dogs.
Mike Richards, DVM

Grape and Raisin Poisonings in Dogs

Recently, there was a letter in the AVMA Journal from Dr. Gwaltney-Brant and others at the ASPCA Animal Poison Control Center discussing grape and raisin poisoning in dogs. Apparently, grapes and raisins can be toxic to dogs when ingested in large quantities.

The grapes and raisins came from varied sources, including being eaten off the vine directly. The dogs exhibited gastrointestinal signs including vomiting and diarrhea and then signs of kidney failure with an onset of severe kidney signs starting about 24 hours after ingestion of the grapes or raisins. The amount of grapes eaten varied between 9oz. and 2 lbs., which worked out to be between 0.41 and 1.1 oz/kg of body weight. Two dogs died directly from the toxicity, three were euthanized due to poor response to treatment and five dogs lived. Due to the severity of the signs and the potential for death, the veterinarians at the poison control center advocate aggressive treatment for any dogs suggested of ingesting excessive amounts of grapes or raisins, including inducing vomiting, stomach lavage (stomach pumping) and administration of activated charcoal, followed by intravenous fluid therapy for at least 48 hours or as indicated based on the results of blood tests for kidney damage.
I have fed my dogs a few grapes every now and then for years, so I don't think there is a need to panic if a dog eats three or four grapes but if the whole bunch is missing from the table one day, it would be good to think about watching for any signs of a toxic reaction.

Michael Richards, DVM

Michal Update: You may wish to give your veterinarian a call if you suspect your dog has ingested  grapes but aren't sure. It's a good idea to know where he is going to be if you might have an emergency later, in case you need to make other arrangements . You both may decide to assume that the dog has eaten the grapes and treat the dog. Whatever the decision, letting your vet know that there is a potential problem going on is a good idea. Newer information from Animal Poison Control has indicated that as few as 7 grapes can be toxic.


Iron Overload

Q: We seem to have a lot of iron in our well water, now that the bacteria situation has been cleared up.  The dishwasher gets stained dark orange inside (Tang Beverage Powder clears this discoloration up nicely, by the way), and the dogs' stainless steel feeding bowls are getting tinged with that color on the bottom.  It also has a slightly metallic odor. Some kind of filter is supposed to help with this and we are looking into this, but I wonder if it will be effective enough, and with the dogs drinking so much water, and information coming out about excessive iron being harmful to folks, do I need to worry about the dogs?

Thanks, Helen
A: Helen-

There are veterinarians who feel that iron overload is a problem among pets and that it would be more commonly diagnosed, if more veterinarians were aware of the possibility. However, water is probably not the source of the iron excesses in pets.  Pet foods often contain higher iron levels that the minimum recommendations but I know of none that have iron levels exceeding the maximum recommendations of the American Association of Feed Control Officials (AAFCO), which provides the guidelines for nutrient contents in dog and cat foods.

Iron oxide, which produces the red color in iron in water, can not be absorbed by dogs and cats, according to the authors of "Small Animal Clinical Nutrition, 4th ed."  I checked online for references, just to be sure and found this web page: ,  which also states that iron in the water is not considered to be a health hazard but provides some advice on how to eliminate iron from the water.

Mike Richards, DVM


Chemical Toxins

Q:  Hi Dr Richards

  My husband last night found some bug bites on his back while on the couch so he spray  some insect killing powder on the whole couch.    The power is said to be organic and would  not do damage to pets.  It contains 88% silocone dioxide. This morning one of my dogs   slept on the couch and I found him licking the powder.  His hair must also have got the  power on.  He licks his feet also.  I am worried if the power is going to be poisonous to him.   If a pet gets poisoned, how long usually will symptoms be shown?  A friend of mine  told me his dog died of kidney problem, and autopsy showed that the animal was poisoned   by a poisoned steak (given by a neigbour) 5 weeks ago.   I also know of a dog who was  given a poisoned cookie  a month before and then she got sick 2 weeks later and then  eventually died of kidney failure.  Could some poisons take so long to be damaging?  If my   dog is OK for the next few days, can I assume the powder is safe.

Also, my dogs sometimes roll over on my neighbour's lawn which are chemically treated   (i.e. contains insect killing chemicals), is the chance of getting poisoned high?  Yes I do try  to watch them but sometime the flex leash is so long by the time I caught them my dogs are  already rolling on the grass.  If my dog then licks his hair, will be get poisoned?

  The second question is recently I began taking my dogs to a leash-free park of the city.  It   means there are always some 5-15 dogs in the park.  Sometimes they drink from the same  bowl of water.  Are there any contagious/skin diseases that I need to watch out for.  All the  dogs are supposed to be vaccinated.  Should I let my dog drink from the same bowl.  Is  socializing with all dogs OK healthwise, assuming they are vaccinated.   Thanks a lot and look forward to your reply ASAP.

A: Lily-

I couldn't find any indication that there have been problems with silicone dioxide toxicity in pets. I think that these products have been shown to be irritating to dogs with asthma, but that isn't a toxicity problem. I suspect there is no worry there.

In the past, there have been reports of a slight increase in risk for lymphoma (a form of cancer) in dogs exposed to a lawn treatment chemical referred to as 2,4-D. This is probably not a problem with low exposure, though.

There are risks of communicable diseases through using a common water bowl. The most likely risk would be infectious tracheobronchitis (kennel cough), which can be vaccinated for. I think that this situation would justify that vaccination. There is a small chance of transmitting roundworms in this manner, so using one of the heartworm prevention medications that also controls roundworms would be a good idea.  Adequate flea and tick control would be more important in dogs playing in an area with many other dogs. Sarcoptic mange could be transmitted in this situation, too.  The overall risk of a serious illness is pretty low. There would also be a risk of trauma due to fight wounds if one of the dogs gets aggressive --- but this is one of those risk/benefit things that you just have to think through. There is a lot of fun for these dogs in this situation too. Most of the time, I think I'd favor letting my dogs have a good time over worrying about small risks, but keeping a good eye out for obviously ill or obviously aggressive dogs and going home on those days would be a good idea.

Hope this helps some.

Mike Richards, DVM


Mushroom Toxicity

Q: Dr. Mike, I  have a few questions about mushrooms.  I have a two year old yellow lab named Reilly.  He weighs about 81 pounds and is very healthy.  He is an inside dog, but we go on a 2-3 mile walk every day, which he enjoys very much.  Unfortunately, Reilly will eat anything and while we walk I have to constantly watch him so he does not eat anything bad for him.  Sometimes, I can't get to him fast enough.  It has been pretty damp here the last couple of weeks and mushrooms have sprung up all over the place.  Reilly has taken to eating mushrooms occasionally and twice in the last two weeks has become very ill.  He has excessive salivation for almost 12 to 14 hours, and also has vomiting and diarrhea.  He really doesn't have any other symptoms.  He is somewhat lethargic, but not extremely so.  The symptoms usually resolve within 14 hours.  He is less active for another day or two, but then returns to his normal, very active self.  Both incidents happened on weekends and late in the evening after the vet's office had closed.

Should we induce vomiting in this situation?  Reilly doesn't vomit until a few hours after he starts salivating and he seems to feel much better after he does vomit.  In fact, the diarrhea hits him faster than does the vomiting.  I don't know what kind of mushrooms he is eating, but could they have any long term effects on his health?  Could anything else be causing this?  Should we take him to the vet's office immediately or let the situation resolve itself (as we had been doing)?

A: Alyssa-

Mushroom toxicity does occur in dogs and it can be fatal if certain species of mushrooms are eaten. Amanita phalloides  is the most commonly reported severely toxic species of mushroom in the US but other Amanita species are toxic.  They can cause severe liver disease and neurologic disorders.  The recommendation is to induce vomiting when these mushrooms are ingested and to give activated charcoal, as well. Supportive treatment for liver disease may also be necessary.

There are probably species of mushrooms with less toxicity but enough to induce the milder symptoms you are seeing. Inducing vomiting would still be a good idea, I think, when these species of mushroom are eaten. It is possible to induce vomiting using hydrogen peroxide given in small amounts until the dog vomits or by using syrup of ipecac (it takes about 1 teaspoon of ipecac syrup per 10 lbs. of body weigh to induce vomiting, on the average so it can be hard to give enough of this --- and overdosage can cause heart problems so it does have to be measured).  Apomorphine is a good choice for inducing vomiting, too -- but usually only available through your vet and it is pretty expensive.

I can't really think of a another cause for excessive salivation along with vomiting and diarrhea that doesn't involve some sort of toxin but it is possible that there is something else going on. It would be a good idea to talk this over with your vet on the next visit, so that he or she has these episodes in the medical history for future reference.

It is hard to stop dogs from ingesting odd things but you should keep trying to prevent mushroom ingestion, as well as you can.

Mike Richards, DVM


Napthalene or Moth balls in Vacuum Bag

Q: Dr. Mike,

Can I put 2 or 3 month balls in my vacuum bag to kill fleas?

A: M-

I have seen this suggestion, but I have also seen, somewhere, a warning that napthalene is pretty toxic and that it will produce toxic fumes if placed in a vacuum bag.  Some people also recommend using a flea collar in a similar manner and there are similar warnings about doing this.  It would probably be better just to use a good flea and tick control product, such as Frontline (tm), Advantage (tm) or Program (tm) on your pet, consider use of a premise   flea killer and throw the vacuum bags out a little quicker than your normally would, if fleas are a problem in your house.

Mike Richards, DVM

Since we received this email I have been checking the  ASPCA National Animal Poison Control Center  webpage to keep a check on their investigation. Please read the statement at the bottom of the page.


Febreze Is Not Dangerous to Pets

Q: Dear Mike: I received this from one of my e-mail friends. I'm forwarding it on to you. I know that everything you hear on the Internet is not necessarily true, but this sounded pretty ligament. Thanks for your time. Andrea B

 Fabreze rumor

 "There have been multiple instances of dogs and birds who have died or became very ill after being exposed to Febreze, a deodorizer/air freshener. Febreze contains zinc chloride, which is very dangerous for animals. "

This is from a friend of mine at UVA - her dog died and this is what the vet had to say.  If you have a cat or bird, FEBREZE (odor spray) is TOXIC!!!! This has been confirmed by a vet.  It will kill your animal.  A friend's dog died unexpectedly and the vet strongly suspects this product as well. ''
A-The National Animal Poison Control Center has a note on their website which says that they have not been able to find any evidence to date that there is a risk to pets from Febreze.

The URL for the NAPCC is

Mike Richards, DVM

May 26 Update - Fabreze statement  from the Animal Poison Control Center

Date:       March 26, 1999

To:          Whom It May Concern

Subject:   Febreze™ Fabric Refresher  

Recently there have been comments and discussions posted on the Internet suggesting that the use of Febreze™ Fabric Refresher in households is dangerous to animals. We have issued the following statement in order to help disseminate accurate information:

"Veterinary toxicologists at the ASPCA National Animal Poison Control Center are conducting an on-going investigation into claims that use of Febreze™ in the home caused the death of several pets. All information reviewed to date suggests that there is no evidence that Febreze™ represents any risk to pets when used according to label instructions. Presently, the center considers the product safe to use in households with pets. As with any cleaning product, the center recommends that birds be removed from the room until the product application has dried and the area has been ventilated. Please call 1-800-345-4735 if you have any questions or have a pet that you suspect is experiencing problems or visit us at"

Please photocopy this letter or download our statement from our web site and pass the correct information on to other friends of animals.


Steven R. Hansen, DVM, MS Diplomate American Board of Veterinary Toxicology Senior Vice President

Chocolate Toxicity

Q:  A veterinarian  sent me a e-mail two days ago telling me that my for dosages Chocolate toxcity were incorrect. Would  you please tell me what dosage is acurate.
 Thank you.   Dr G
A: Dr. G

The LD50 -- dose at which 1/2 of the dogs exposed to a substance will die --- is about 100mg/kg for chocolate. The dose that causes signs of toxicity, such as excitement, increased urination, muscle tremors and rapid heart rate may occur at a lower dosage.
The other problem with dogs eating chocolate is that a lot of formulations of chocolate are high in fat and dogs often get enteritis or pancreatitis following ingestion of a lot of milk chocolate.
Your dosages of 44mg theobromine/oz for milk chocolate, 150mg/oz for semi-sweet chocolate and 390 mg/oz for baking chocolate match the dosages that I have seen published. Using a dose of 100mg/kg as the toxic dose the toxic dosages per pound of body weight for dogs work out to be roughly:
1 ounce per pound of body weight  (2 ounces per kg of body weight) for milk chocolate.
1 ounce per 3 pounds of body weight ( 1 ounce per 1.5 kg body weight) for semi-sweet chocolate
1 ounce per 9 pounds of body weight ( 1 ounce per 4 kg) for baker's chocolate.
So the dosages I am familiar with match what you have included in your email for death by chocolate. Toxic signs may occur at lower dosages. The best estimate that I have seen for this is that clinical signs may develop in some pets with dosages as low as 10% of the LD50 dose.
I have been practicing for 20 years and I do not recall having a patient die from ingestion of chocolate but I have seen some very excited dogs and I have seen some dogs that probably would have died from the secondary enteritis without treatment.
I have talked to veterinarians who feel that they have seen dogs that died from heart problems, pancreatitis or other complications following chocolate ingestion even though the dogs ate less than the theoretical toxic dose.
I think that the chances of causing a toxicity with milk chocolate are very very low and I don't think it is a big deal if my clients share their M&Ms with their pets but semi-sweet chocolate morsels and baker's chocolate should be put where pets and small children aren't likely to find and ingest them.
I hope this is the information you were looking for.

Mike Richards, DVM

Antifreeze Poisoning from Ethylene Glycol

Q: Dear Dr Mike

Recently in Australia a number of show dogs have been poisoned by antifreeze.  People have assumed that dogs have been poisoned on purpose by some unknown party contaminating dogs water bowls at shows. It has also been suggested that this may have occurred by air-conditioning systems. eg: Home & Cars etc.

Could this be the case? What are the symptoms to look out for & how long does it take for symptoms to occur after ingestion? Your reply to these questions would be gratefully received.

Margaret R
A: The most commonly used antifreeze compounds contain ethylene glycol, which is toxic to dogs and cats if ingested. The minimal lethal dosage for cats is 1.4ml/kg of body weight and for dogs 4.4 to 6.6 ml/kg of undiluted ethylene glycol, according to Thrall, Grauer and Dial in Kirk's Current Therapy XII. This means that 1 teaspoonful of antifreeze (5ml) could kill a 7 pound cat. Antifreeze is normally diluted for use in automobiles so more of the diluted solution would have to be ingested to achieve toxic levels. Unfortunately, antifreeze seems to be palatable to dogs and cats and ingestion of large amounts of the solution can occur.

Ethylene glycol has similar effects to ethanol (the alcohols imbibed recreationally by humans). However, it is broken down in the liver into different compounds than ethanol and these metabolic products cause damage to the kidneys and are more toxic to the central nervous system than the ethylene glycol.

Antifreeze poisoning normally occurs when pet become exposed to antifreeze leaking from a car's cooling system or when antifreeze is changed. Sometimes antifreeze is placed in home plumbing systems when heat will not be maintained during winter months (such as a summer cottage). When this is done it is extremely important to remember to flush the system well prior to letting pets in the house. Pets have been exposed to antifreeze poisoning maliciously in some instances, as well.

There is at least one brand of antifreeze sold in the U.S. that does not use ethylene glycol and is considered to be safer for pets.

After exposure to the ethylene glycol clinical signs will develop in as short a time as 30 minutes to approximately as long as 12 hours, depending on the dose ingested. Depression, signs of intoxication similar to alcohol ingestion, vomiting, depression, coma and death may occur among the initial signs of poisoning. These signs normally last less than 12 hours in dogs causing some owners to think the danger has passed. Cats are less likely to recover from the initial signs. After the central nervous system effects are over, the kidneys are damaged by the antifreeze. In cats this may seem like a continuous thing because the kidney effects often show up just as the CNS signs would have diminished. In dogs the kidney problems usually show up one to three days after ingestion of the antifreeze. Formation of urine drops off until urine is not produced at all. This severe renal failure causes vomiting, sores in the mouth, a noticeable increase in oral odor, severe depression and then eventually coma and death.

The really bad thing about antifreeze poisoning is that treatment must be initiated very promptly for the pet to survive. Dogs do best if treated within five hours of ingestion of the antifreeze. Cats need to be treated even sooner. The chances of survival diminish rapidly 8 hours post ingestion in the dog and 4 hours post ingestion in cats. For this reason, it is extremely important to consider the possibility of antifreeze poisoning almost any time there are unexplained central nervous system disorders that occur acutely in dogs and cats.

There are tests specifically for ethylene glycol. An "in-house" test kit is available to veterinarians and local hospitals are often willing to test for this toxin on an emergency basis when exposure is suspected. Examination of the urine reveals crystals that are highly suspicious of ethylene glycol exposure about six hours after the toxin is ingested but waiting for these to show up places the pet at risk. Looking for crystals when the timing of exposure is unknown can give good prognostic information, though.

Treatment for this condition is best done with 4-methylpyrazole (4-MP, or fomepizole (Antizol-Vet(TM)), which was recently approved for use in dogs. This medication competes for the liver enzymes that break down ethylene glycol and slow its metabolism down, keeping the serum levels of the toxic metabolites down and allowing them to be excreted safely when used early enough. If 4-MP is not available treatment consists of using ethanol, usually intravenously. Ethanol also competes for the same enzymes and inhibits breakdown of the ethylene glycol. The problem is that ethanol itself causes severe central nervous system depression at the dosages necessary and this can have an additive effect with the ethylene glycol. It is still much better to treat when exposure is know to have occurred or is documented by lab work, though.

Antifreeze poisoning causes a terrible death and it is inexcusable for a human being to inflict that kind of suffering on a pet intentionally. I can not begin to understand why people would do such a thing but have personally dealt with at least one case of antifreeze toxicity in which a dog was intentionally poisoned.

Mike Richards, DVM

Call Poison Control

Q:  My two rotten dachshunds took a tube of ArthriCare (Del Pharmaceuticals) from beside me and punctured the tube while playing with it. I fear the ingested some of the cream. I have a call into the emergency vet center, but hoped I might get an answer from you too. The warnings say "if ingested call a Poison Control Center immediately" -- well, I am in Panama (yes the country)...but does not say what poison to treat for. The ingredients are listed below. Active Ingredients: Menthol 1.25%, Methyl Nicotinate 0.25%, Capsicum Oleoresin (containing Capsaicin 0.0.25%) Inactive Ingredients: Aloe Vera Gel, Carbomer 940, Cetyl Alcohol, DMDM Hydantoin, Emulsifying Wax, Glyceryl Stearate SE, Isocetyl Alcohol, Myristyl Propionate, Propylparaben, Purified Water, Stearyl Alcohol, Triethanolamine.

A: I suspect your dachshunds are probably fine but it is always good to call a poison control center.

A good number to keep on hand: National Animal Poison Control Center ( 1-900-680-0000)

There is a charge for calling the center so listen to the details on that when you call. I am not sure you can call directly from Panama but you probably have figured all of that out after living there.

It is actually pretty hard to look up many toxins without access to a poison control center. Of the ingredients listed, I could only find capsaicin and nicotine (which probably isn't the same thing as nicotinate) in the references I have at home. I'm not sure why the dogs would like something containing capsaicin since it is the "heat" producing compound.

Hope all is well.

Mike Richards, DVM

Sugar Overload

Q: I really love you web page!! As for my a medical student I have been going round and round trying to figure out what happened to my 1 yr old Jack Russell Terrier last week. On Wednesday she went 'garbage diving' and ate an entire box of brown sugar + god knows what else. On Thursday, she had copious, cholera-like, watery diarrhea early in the day, then she progressively lost her spunk even though she was drinking fluids. During Thursday evening, she had a fever of 104.2, went into stupor, stumbled over herself, irregular gait, inability to get comfortable (stay still) etc. Although she was still responsive to her name and her favorite squeaky toys. Abdomen was distended, full. I took her to the ER where they said her reflexes were depressed, she had a fever, and was in danger of becoming dehydrated. Liver enzymes were just outside the high range of normal, and her WBC was elevated. Vet gave her a shot of ampicillin, and I took her home. During the night I gave her water, but she would not eat. Friday....much better prognosis, but still unsteady on her feet. Eye contact was more pronounced and she readily accepted watered-down baby cereal to which some salt was added. She ate/drank 3 bowls of it. After the first bowl, she had a seizure-type event which subsided and was not repeated. By Sunday, she was back to her JR terrier self, bouncing off the walls, What could have caused my dogs illness? Was it bacterial toxin from the garbage? (Can dogs get botulism or salmonella) Was it the dehydration ? For what it's worth, the Yellow Lab that shares her space has not been sick at all. Thanks for you insight and help! Dawn

A: Dawn- I think it is very likely that a whole box of sugar could lead to an osmotic induced dehydration or that it could lead to a bacterial overload or imbalance in the digestive tract that led to diarrhea. Dogs do get Salmonella and other food poisonings, so that is possible, too. Even fermentation of the sugar in the digestive tract seems possible, with excessive gas formation leading to pain and digestive problems and systemic signs. I'm just guessing at these things because I don't really have a reference that discusses ingestion of large quantities of sugar! It always amazes me how many things happen that aren't covered by the textbooks.

Hope this helps some.
Michael Richards, DVM

Organophosphate Poisoning or White Shaker Dog Syndrome

Q: Our 10 month old Westie is being treated with prednisone for white shaker dog syndrome as of this morning. He has also been tested for lead poisoning (results pending). Our neighbor had their lawn treated with insecticide recently. How would our Vet determine whether our puppy has "organophosphate poisoning" as opposed to White Shaker Dog Syndrome, and how would it be treated? Our dog seems VERY sick and we are very frightened. Any thoughts or information will be appreciated!

A: Organophosphate poisoning has some signs such as excessive salivation, "wet" respiratory sounds, diarrhea, slow heart rates and miosis (pinpoint pupils) which help to distinguish it from other conditions. To aid in the diagnosis it is also possible to test cholinesterase (ChE) levels in the bloodstream. A reduction of 50% from "normal" levels is indicative of problems and levels of 25% or less are very very suspicious for organophophate poisoning.

Mike Richards, DVM

Broccoli Toxicity

Q: Dear Mike, This is follow-up on yesterday's conversation just to remind you. If the stuff is a no-no for dogs as well as ex-Pres. Bush, maybe it's worth noting in your web site. Thanks, NvB

A: It is always good to remind me of things -- I had forgotten.

Broccoli toxicity has been noted in livestock. Apparently in California it is widely available at certain times and the dairy cattle there are fed broccoli due to this. If the percentage of broccoli in the diet exceeds 10% it can cause gastrointestinal upsets and if it exceeds 25% it is fatal.

I could not find any references to problems with broccoli in small animals, probably because no one feeds them more than 10% of their diet as broccoli or possibly because they don't have rumens and therefore don't digest the broccoli as thoroughly.

The toxic ingredient in broccoli is isothiocyanate and it is reported to be a pretty potent gastrointestinal irritant.

So G. might be right. But I did find several references suggesting that broccoli should be fed to pets because of the bioflavinoids in it and their cancer fighting capabilities. So he might be wrong.

Personally, I wouldn't worry about it unless you are planning on feeding a lot of broccoli at one time to Kate. But your daughter might want to follow her vet's advice or find out if there is more evidence of toxicity than I can find.

Mike Richards, DVM

Chocolate Toxicity

Chocolate contains a xanthine compound, theobromine, that is toxic in sufficient quantities. Examples of other xanthine compounds are caffeine and theophylline. The toxicity from all of these compounds is similar.

It takes a fairly large amount of chocolate to cause problems. In "The Handbook of Small Animal Practice" by Dr. Rhea Morgan, the following data is given:

The toxic dose of theobromine is about 100 to 150mg/kg

Milk chocolate contains 6mg of theobromine per ounce. Semi-sweet chocolate contains about 22mg/oz. and baking chocolate about 35 to 45mg/oz.

From this it is pretty easy to see that milk chocolate poses only a minor threat while the other forms of chocolate can be a bigger problem.

Xanthines affect primarily the central nervous system, the cardiovascular system and peripheral nerves. There is a diuretic effect as well. So the sign seen with toxicity include hyperexitablility, hyper irritability, increased heart rate, restlessness, increased urination, vomiting and muscular tremors or tenseness. Under some circumstances these signs can lead to secondary problems like hyperthermia. In severe cases, seizures or cardiac arrest can occur. Death can result from severe intoxication.

There is no specific antidote for this poisoning. Inducing vomiting can help if the ingestion is known and has occurred within one to two hours. Administration of activated charcoal may inhibit absorption of the toxin from the digestive tract. It may be necessary to use medications to control the effects of the poisoning, especially seizure control medications, oxygen therapy, intravenous fluids, and medications to control the effects on the heart.

With ingestion of milk chocolate, diarrhea is a common secondary problem. This may require therapy and often occurs 12 to 24 hours after eating the chocolate.

If you suspect chocolate poisoning and your dog or cat is showing clinical signs of the problem, it is important to contact your vet.

Michael Richards, DVM

Q: Dr. Mike, My friend has three Shih Tzus (one adult male, one adult female, and a 3 month old male) and they just managed to gobble up one and a half chocolate bars while we weren't watching. My friend is pretty worried and claims that chocolate will kill them. I've never heard this before. Assuming they live, can you tell me how serious this could be if they do it again, and what actions can we take to help them? Mike

A: Mike- I'm sure the dogs are fine by now. Milk chocolate rarely contains enough chocolate to pose a serious threat to dogs from chocolate toxicity. A lot of dogs get pretty good cases of diarrhea after eating chocolate treats in large quantities, though. Baker's chocolate is concentrated enough to pose a threat to dogs and they can die from chocolate toxicity. So your friend is right about the possibility of chocolate toxicity but it is just not likely with milk chocolate ingestion, except in very large quantities.

Mike Richards, DVM

Lead Poisoning

Lead is extremely common in the environment. It is found in linoleum, caulk, toys, lead based paint (esp. paint from prior to 1977), solder, batteries, weights, golf balls, bullets and other items. This toxicity must be considered as a possible diagnosis with a variety of clinical signs, including loss of appetite, abdominal pain, diarrhea and vomiting. Especially if these gastro-intestinal signs are accompanied by neurologic signs, such as blindness, seizures, difficulty walking, tremors, or usual behavior. This can be a cause of increased drinking and urinating as well. Since these signs occur with a number of other diseases, it is easy to miss lead poisoning. Be sure to tell you vet if there is a possibility of lead poisoning that you are aware of, such as living in an older house or a dog that tends to eat unusual objects.

Lead poisoning interferes with certain enzymes in the body. It causes the red blood cells to be weak and easily destroyed. Anemia can result from this but is usually mild. Blood vessel irritation leads to the other clinical signs.

Most of the time lead poisoning occurs in younger dogs because they are the most likely to ingest unusual items such as fishing sinkers or lead putty. Older homes that have been remodeled recently are a common cause of lead poisoning. Older buildings are always a risk for lead based paints and items like lead sash weights.

Lead poisoning can be diagnosed through lab tests of the blood of affected pets. It is a treatable condition but the treatment can be expensive, especially if extensive supportive care such as IV fluids are necessary for extended periods. Retreatment is sometimes necessary.

If there is lead poisoning in a pet, it is important to consider the possibility that it might also occur in children in the household if it is related to old paint or lead containing objects available for ingestion. Please tell you family doctor or local health department if your pet is diagnosed with lead poisoning and you have children.

Michael Richards, DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...