Toxic to Cats


also see Poisoning and Toxicosis in cats

also see Poisoning and Toxicosis in dogs

also see Sudden death in cats

also see Sudden death in dogs

Please don't Feed 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


In cats, the most common poisoning that we see in our practice at this time is permethrin poisoning. This occurs when clients use "spot on" flea control products containing permethrin and labeled for use in dogs on their cat. This must be a fairly easy mistake to make because we see two or three cats a year with permethrin toxicosis. This causes severe tremoring, salivation and seizures in cats. It is unclear what percentage of cats who are treated with permethrin based flea products die from the exposure but some do. Most cats will respond to treatment with muscle relaxants such as methocarbamol and diazepam (Valium Rx). There is no specific antidote for permethrin poisoning. Thoroughly washing the permethrin off the hair and skin if it is accidentally applied can prevent poisoning and doing this helps even after clinical symptoms of permethrin poisoning have occurred.

Once in a while small dogs develop muscular weakness after permethrin products are applied but this is a transient effect and dogs are generally not considered to be as susceptible to permethrin toxicosis as cats are. The best way to avoid this poisoning is to read the label of all flea control products before applying them to any pet, but especially before applying them to a cat. 11/02/2004


Easter is a dangerous time for cats, because Easter lilies are very toxic to cats. Other lily species, including day lilies, are also toxic but exposure to them seems less common. Why cats are so susceptible to poisoning by lily species has not been fully documented but eating these plants causes severe kidney failure. Most cats will also have gastrointestinal irritation that causes vomiting. This is rapidly acting toxin and it is necessary to act quickly if your cat is observed eating lilies or if vomiting or signs of GI distress occur and ingestion of lilies is a possibility.

If a cat has not vomited on its own after eating lilies it is best to induce vomiting and then to try to absorb as much of the lily toxin as possible using activated charcoal. The most important part of treatment for lily poisoning is intravenous fluid therapy to help the kidneys continue to function enough to eliminate the toxin. The only alternatives if kidney function does stop is hemodialysis or peritoneal dialysis, which must be kept up until kidney function returns. There are some reported cases in which this has happened. If you have cats it is best not to have any lily species in your house or garden.

Dr Mike Richard, DVM 11/02/2004

Pop-top cat food cans - possible hyperthyroidism correlation

Question: Hi Dr. Mike: Truly - this is one of the very best of your monthly reports. Your openness is welcome - indeed! Yet, with I have to ask you for an explanation about the "pop top cans"! Please explain? Surely *a* can cannot be responsible for what is happening? Right? Keep up the great work. Saludos de méxico, Charlotte

VetInfo Digest June 2004 New products and information Avoid pop top cat food cans? A study in the March 15, 2004 AVMA Journal (Edinboro, et al.) pointed out a correlation between the use of pop-top cat food cans and the subsequent development of hyperthyroidism in cats. This study merely points out a statistical correlation and doesn't prove that this relationship is certain but if you wish to be cautious about the possibility there is no harm in switching to cans that have to be opened with a can opener. Most cat foods are available in both types of cans, although it may be necessary to buy bigger can sizes to avoid the pop-tops.

Answer: Charlotte- When they make pop-top cans they line them with a chemical called bisphenol-A. I think it seals the lid under the pop top. Anyway, this chemical is hypothesized to be the cause of hyperthyroidism related to the use of pop top cans. It isn't used in regular cans that have to be opened with a can opener. Four or five years ago a study of hyperthyroidism showed a correlation between feeding cats canned food and hyperthyroidism. This was further studied in a report published this year (March 15 2004 AVMA Journal) which asked what kinds of cans were used and it was noted that the increase in hyperthyroidism is only in cats fed from pop-top cans. The major difference between the cans is apparently the use of this chemical, so it is thought to be the culprit. Before that is confirmed further study will have to be done, though - and like all these types of studies it is conceivable that something entirely different will be found. Mike Richards, DVM 6/11/2004

Lawn chemicals and cats

Question: Dear Dr. Richards- We are new subscribers with ten cats. We'll try not to overwhelm you! The cats are allowed out at various times of the day, always brought in at night. Since we have lived in this house (3 years) we are using a lot of lawn chemicals, the usual pesticides and herbicides available at the local home store, and the house is treated with termite chemicals yearly. Our vet says cats are very sensitive to these chemicals and we should be cautious...common sense, now that I think about it. For some reason my husband, who loves the cats, is loathe to give up using these chemicals. He insists that when instructions are followed these things are safe. How much trust should we put in these companies testing and research? I am thinking we should not be using this stuff at all. Have you run across many problems over the years which can be attributed to these chemicals? It seems like it would be rampant since we are as a society using so much of the stuff. I guess I am looking for another opinion to support my stand on this.

We have one cat (Wally) with neurological type symptoms which is why I started to think about this-he's being extensively tested now. Our vet says he doesn't think this is Wally's problem, since his liver function is good, among other things. I will let you know what his diagnosis finally is, if it seems like it would help anyone else. Thanks for your wonderful resource! Susan

Answer: Susan-

There are studies that indicate that a particular lawn care chemical,2-4-D, is linked to a higher incidence of lymphoma in dogs and humans exposed to it. The statistical significance of the link has been questioned in some other reports, as is usually the case with these sorts of things, but I think it is reasonable to say that there is an increased incidence, just not as high as some of the reports suggest. I have no idea how often this chemical is used by lawn care companies or how often it is found in the ingredients of products made for the homeowner to apply. It is reasonable to suspect that if the link in dogs and humans is accurate then it could occur in cats, as well.

There are suspicions among researchers, veterinarians and physicians about other lawn care products, especially insecticides and pesticides. There is no question that exposure to adequate doses of these products (usually direct application like the pet getting into the product, accidentally being sprayed with it, etc) can cause problems but there isn't a lot of information on the long term effects that isn't speculative. There are many people who are speculating that there are long term effects that just aren't being reported, though. Whether they are right or not is just hard to say.

For an individual patient, establishing a link to something like lawn chemical exposure is just about impossible. So it is best to look for other things as your vet is doing.

Cats are more susceptible to reactions to organophosphates and permethrin than dogs are. These are insecticides found in some garden and lawn products. We have seen several cats with diazanon toxicity after it was applied around the base of houses. I am not sure what insects it is used for in this manner but when it is used cats should not be allowed into the area where it was applied, at least until it should have dissipated. I suspect that the termite chemicals aren't good for cats, either, but that they are usually applied in areas not accessible to the cat.

So the short answer is that there does appear to be proof that at least one lawn care chemical can increase the risk of one form of cancer with long term exposure. Whether you can generalize from there and assume that there are likely to be other undiscovered risks is not as clear. Insecticides can be toxic to cats. You definitely should store the chemicals safely and follow directions for application carefully.

Mike Richards, DVM 5/29/2001

Onion and Garlic toxicity in dogs and cats

Question: 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?


Answer: 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 11/15/2001 Toxic plants and cats

Question: Hello, I just got a new cat and am wondering if there are any kinds of flowers that are not poisonous to cats. My sister told me that Poinsetta plants are poisonous to cats, so I am getting rid of one that I got from a friend for christmas. Are roses poisonous to cats also? What flowers or plants are okay? I know this is an odd question, but I thought you might know the answer or at least know where to look. I love flowers but I don't want to bring any into my house that could poison my cat. : )

Thanks so much! Kimberly

Answer: Kimberly-

I think that poinsettia plants have gotten a bum rap. If they are toxic, it is a very mild toxicity. I have never had to treat a case of poisoning from this plant. The plants that worry me most are Easter lilies (actually all lilies worry me because there are several poisonous ones and I can't identify types of lilies). Plants that are reported to cause severe problems with oral ulcers or pharyngeal inflammation include Dieffenbachia (dumbcane), philodendron and elephant ears (Colocasia). Mistletoe, castor beans, aloe vera and English ivy are supposed to be able to cause gastrointestinal discomfort. This is true for daffodil and iris bulbs but I don't think cats are likely to eat the bulbs. Mountain laurel and azaleas are also GI irritants but aren't probably available to many housecats. Japanese yew is really toxic but is also not usually available to housecats. There are many other toxic plants but most are not used as house plants.

There is a long list of non-poisonous plants that can be downloaded from the web site but it is for a the PalmOS. It originally came from Dr. Jill Richardson of the National Animal Poison Control Center, and there may be a version there that is browsable. There is a shorter list of poisonous plants but since you are looking for safe plants the first list seems to be more useful as the poisonous plant list is not complete.

In our practice the plant toxicities that I can remember treating in small animals are Easter lily, marijuana, mushrooms (only in dogs, so far) and onion toxicity (cats).

Hope this helps some.

Mike Richards, DVM 2/10/2001

Toxicity of household cleaning products

Question: Dear Dr. Mike, I am a new subscriber, but have had cats for many years. On another forum, I was chastised about using Lysol or Pine-sol to clean up linoleum flooring after litter box mishaps. I am curious about any studies of the health hazards of this type of product to cats. Of course, I do not allow my cats to walk in the area while I am cleaning up. When I use them, I sponge wipe the area with water afterwards and dry with paper towel.

Thanks for any info. John

Answer: John-

Veterinarians appear to be of two minds when it comes to these household products.

Cats do not process phenols well, which both products contain. Therefore, sufficient exposure to these chemicals could cause problems, including local irritation of the skin or softer mucosal tissues of the mouth or digestive tract. Liver toxicity may also occur.

Given this, some vets believe that these products should not be used at all where a cat might contact a surface cleansed with them. Other vets believe that if the surface is rinsed and dried, that the chance of sufficient exposure to cause a problem is very low.

I think that there is a case for both arguments, since I have read of a couple of accidental exposures to the cleaning solutions directly, usually due to inadvertent spills. On the other hand, in the entire time I have been in practice I do not remember treating a toxicity case from either product, making me think the potential for problems is pretty low. If you chose to use these products be careful, as you have been. If you want to use other disinfectants, it is probably best to be careful with them, too.

Mike Richards, DVM 10/31/2000

Napthalene or moth balls in vacuum bag

Question: Dr. Mike,

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


Answer: 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 6/12/2000

Liquid Mercury

Question: Dear Dr. Mike,

I broke a thermometer yesterday and have been trying to clean up and find all the little balls of mercury ever since. My concern is how dangerous and harmful is mercury for pets? I have 3 cats and my own vet said that mercury is toxic but he doesn't know how dangerous it might be to them. I have tried to clean the room as best as I can but I am still afraid that there might be little bits of it still around and so right now, I am still not allowing the cats back into this room. Have you any advice on what I should do? How hazardous is mercury? The best way to find all the pieces of it? What kind of treatment should be used if it is ingested by the cats?

Thank you Vicky

Answer: Vicky-

Mercury in its liquid form is really not all that toxic. In fact, people used to survive being given liquid mercury orally as a cathartic -- often more than once. Mercury in organic compounds is much more toxic to mammals and that is where the bad reputation for mercury comes from. That and situations in which people were exposed to elemental mercury over long periods of time, such as people who made hats as a career (mad hatters). However, it is still a good idea to clean up the spill carefully and dispose of the mercury.

Mike Richards, DVM 2/14/2000

Mouse Poison

Q: Dr Mike,

If a mouse eats poison (Decon) and the cat eats some or most of the mouse, can the cat be poisoned as well? I live in the country and rodents are sometimes a problem. I hate to use poison, but it's the only thing that's really effective when the field mice invade.


A: Melissa-

With the newer mouse poisons it is possible for a cat to get a toxic dose by eating mice poisoned with the mouse poison. I am not sure how high the risk is but there have been reports of this occurring so there is at least some risk.

Mike Richards, DVM


Q: I know you will probably not respond as I plan to go to the vet tomorrow, but I would like to know your opionion of this situation. I had owned a male-fixed cat for 6 years and had recently moved to an apartment in a condominium with a backyard. The male cat had been indoors for the past two years, but was raised in the country. He, unfortunately, wasn't current on his shots, but had the required shots in his first two years. He enjoyed the garden and the grass (it's walled in) about 20' x 40'. About two months later I noticed he wasn't eating. It took a little while to notice since both my roommate and I feed him dry food. I took him to a new vet and the doctor put him on an IV to feed him and rehydrate him. After testing, my kitty had many time the normal levels of many chemicals, in fact, they were critical. My vet suggested that it could not have been a poison, that the only things that could have produced these levels would be something like anti-freeze which would have had an immediate effect, and that he concluded that it was cancer and it was already very severe. (although the illness happened quite suddenly) Sadly, my cat past away two days later.

A few months later, I got two small kittens. I decided to keep them as indoor cats and they have been quite happy. I have had them for about three months and they have had their shots. They are quite normal and happy little kittens. Last week, as I went into the garden they ran out to explore, they were not out more than five minutes (as I chased them) and got them back into the house. Every day they finish their IAMs kitten food that I leave for them in the morning and feed them again at night. Yesterday, and today, they did not eat. Tonight I fed them some tuna fish which one eat and started purring, and the other nibbled at. The sister has gone to the bathroom (urinated) while her brother has not. The cats still seem active and normal, and not under too much stress, but I'm sure this won't continue.I find it hard to believe it could be coincidence? Is there a toxin in the garden? (I have looked for anything suspicious, but can't find anything) - Rat poison or a pesticide? If there is, the cats did not ingest anything. Or could it be something inside that is just taking time? What do you make of this? thank you for considering.

A: Rat poisons do not usually cause kidney failure (which is what I am guessing the first cat had due to the treatment and mention of anti-freeze). They usually cause bleeding, either internally or externally. This can happen as long as 3 to 5 days after ingestion of the toxin but it still seems unlikely. The only other toxin that might cause these signs I can think of is mushroom poisoning. This isn't too common but it does occur.

There are diseases that could lead to the symptoms seen, such as feline infectious peritonitis (FIP) or feline leukemia virus. The FIP virus is pretty stable in the environment and it might be possible as a problem if your original cat died from it. Since your vet didn't mention it as a possibility it is probably not too likely. You might want to ask about this if the kittens still seem sick or don't respond to your vet's treatment.

I am hoping all is well by now.

Mike Richards, DVM

Are cockroaches toxic

Q: Dear Dr Mike,Can cochroaches harm cats? My cat Leon'ardo and I can not understand why loves to devour cochroaches then after tries to spit them out with a bit of throth. I have tried to stop him but it is too late YUK! I have to rinse his mouth out with water and give him a bowl of warm milk to get rid of that acidy smell. There are 3 types of cochroaches brown, red and black. I am concerned in case some of the cochroaches have eaten bates or have been sprayed I however DO NOT use any sprays I do have bates but they are orgainc honey and wheat by Mortein. I took that into account for Leo'. Please ease my nerves! Kindest regards Y. Austalia

A: I can not find any information suggesting that cockroaches are toxic but there are over 4000 species, so it is hard to be absolutely certain. If you are interested, there is a book, "The Complete Cockroach" by D. G. Gordon. You can order it from Ten Speed Press, P.O. Box 7123, Berkeley, CA 94707. It costs $11.95 (U.S.) Mike Richards, DVM

Rodenticide Toxins

Q: My condo building is having an exterminator come to deal with a mice problem. The exterminator plans to use Contrac, with the active ingredient Bromadiolone, which my vet has told me is EXTREMELY toxic to cats. My vet, however, can only look up chemicals if I provide the name to him. I was wondering if you might be able to offer any suggestions of chemicals that are safe for cats, that I could ask the exterminator about (since I don't trust him to give me that info on his own, since he said Contrac was safe). Thanks in advance for any information you can provide; or if you can direct me to another organization or website that may be able to provide such information.

A: I am sorry to take so long responding. I needed to find a reference that listed the currently used rodenticides and like your vet, I had a hard time doing it. I am still not sure that there are not products which are being used that are not listed. There are three major types of rat and mouse poisons being used. There have been other types but I think (I am definitely not sure) that the other products have been removed from the market. It is also possible that the cholecalciferol group is no longer in use as I have seen references to at least one of the brand-names being withdrawn.

Anticoagulants: These toxins cause the mouse or rat to bleed to death by interfering with blood clotting. The classic one is warfarin. Not too many professional exterminators use warfarin anticoagulants anymore because there are rats who have developed resistance to these compounds. Older anticoagulant rodenticides include warfarin, diphacinone, chlorphacinone, pindone and valone. Newer anticoagulants include brodificoum and bromadiolone. These last a lot longer and will kill warfarin resistant rats and mice. They are also more difficult to treat for when a cat or dog ingests them due to the long duration of effect. Vitamin K is antidotal to the effects of these products but it must be given for approximately 28 days for the newer anticoagulants.

Cholecalciferol rodenticides: these are toxic doses of Vitamin D (cholecalciferol). They cause the calcium regulation in the body to be derailed and high calcium levels to build up in the blood stream, causing failure of major body systems (heart, nervous system, kidneys, etc.) It is very hard to treat a patient poisoned with these products. I believe I saw that Rampage has been withdrawn from the market. Hopefully, other brand names such as Quintox and Ortho Rat-B-Gon have been removed as well.

Bromethalin rodenticides: These cause brain swelling through a complicated mechanism of action which leads to the death of the rat or mouse. Cats do appear to be very sensitive to these products in comparison with other domestic species. I do not know of a consistently successful treatment for animal affected by these products, either.

There may be other rodenticides because there have been other formulations used in the past. The only one I can remember is zinc-phosphide compounds which I think produced phosgene gas in the stomach of animals ingesting it. Rats don't vomit easily so it killed them but the theory was animals that could vomit wouldn't be affected. I don't know if this was a valid theory or if these products are even available now.

To sum this up, there are no rodenticides that I know of that are not toxic to domestic animals as well. When it is necessary to use these products it is important to take safety measures which ensure as well as possible that domestic animals can not get to the bait. In addition, cleaning up any dead rodents found quickly so that pets are not tempted to ingest them is a good idea. I think that the newer anticoagulants have enough residual effect that it is possible for a cat to reach toxic levels by eating poisoned mice. Just because there is a treatment, I'd campaign for the anticoagulant rodenticides.

Mike Richards, DVM

Aspirin or Acetaminophen

DO NOT give any cat a non-steroidal anti-inflammatory medication without consulting with your vet first. Acetaminophen is toxic to cats, aspirin is extraordinarily easy to overdose in cats because the half-life of aspirin in a cat is 72 hours (3 days!) and other non-steroidal medications do not appear to have been studied much in cats, probably due to the problems with these two common ones. For arthritis, we do sometimes use aspirin but it must be used cautiously and it is important to know the patient's medical condition well prior to its use.

An example of acetaminophen toxicity in a cat.

The swollen face is common in this type of poisoning

Last edited 04/27/07


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...