Types of Cat Laxative Products

If your cat is constipated, you may need to use a cat laxative. There are several types of products available. Some are available over the counter. Others require a prescription. Which type you use will depend on what is causing your cat’s constipation.

If your cat’s bowel is obstructed, you should not give him a laxative.

Your vet can help you decide whether a laxative is appropriate for your cat and which type will best meet his needs.

These are the types of laxatives you will find.

Bulk-Forming Laxatives

These fiber-based laxatives pass through your cat’s digestive tract undigested. When they reach his colon, they absorb water and expand. This makes his stool larger and softer. The larger size helps his colon contract, aiding in bowel movement.

These types of laxatives are slow acting. They can take up to 72 hours to work.

Mix a small amount with wet food.  Because they absorb fluids, provide plenty of fresh drinking water for your cat.

Most of these are available over the counter. Some examples of bulk-forming laxatives are psyllium (Metamuscil), canned pumpkin and flax seed.

Osmotic Laxatives

These laxatives work by drawing fluid from your cat’s body into his colon. The increased size of your cat’s stool puts pressure on his bowel and stimulates bowel movement.

Because these laxatives draw fluid from your cat’s body, you must be sure to provide him with plenty of fresh water.

Commonly used osmotic laxatives include Lactulose and Miralax. Both are available by prescription.


These products usually contain white petroleum and work by coating the walls of your cat’s bowel and his stool with a water-resistant film. This creates a lubricating effect, making the stool pass easier. Some products also contain a stool softener which causes your cat's stool to absorb water. The size of his stool increases, making it easier to pass.

Lubricants are commonly used as hairball remedies as well.

Long term use of these products can interfere with your cat’s ability to absorb fat-soluble vitamins like vitamins A, E and D.

It is common to give 1/3 to ½ a teaspoon a day. You can give these products with a small amount of food, but because they can interfere with nutrient absorption, it is best to give them on an empty stomach.

Lubricant laxatives are usually available over the counter and include Petroleum Jelly, Laxatone, Kat-A-Lax and Petromalt.

Stool Softeners

These are salts that decrease the surface tension of your cat’s stool. Allowing it to more easily accumulate water. Using excessive amounts of these laxatives can cause your cat diarrhea.

Docusate sodium or DSS is an example of a stool softener. It is available by prescription.


These laxatives work by introducing an irritant like bisacodyl into your cat’s bowel.  This stimulates the nerves in the lining of his bowel walls, causing them to contract. This type of laxative usually works quickly, but can cause an unsafe loss of electrolytes and dehydration.

Bisacodyl is available without a prescription.

Cisapride, another stimulant laxative, activates the release of acetylcholine. This, in turn, stimulates the smooth muscles of your cat’s digestive tract to contract. Cisapride is available by prescription only.

Constipation is an uncomfortable and sometimes serious condition for your cat. Your vet can help you choose which of the types of laxative are right for him.