digestive system (gastrointestinal tract)

The Classic Comprehensive Handbook of Cat Care




Vomiting is the forcible expulsion of stomach and/or intestinal contents through the mouth. It is important to try to distinguish between true vomiting and regurgitation, which is the passive act of returning the contents of the esophagus or pharynx through the mouth. This distinction will help your veterinarian make a diagnosis if home treatment is unsuccessful. Vomiting is a sign of various illnesses, not a disease in itself. For example, vomiting may accompany thyroid disease, liver disease, kidney disease, cancer of the bowel, intestinal parasite infection, or chronic inflammation of the intestine.

Vomiting occurs commonly in cats, and it is often accompanied by diarrhea. It seems to be caused most often by irritation of the stomach, which veterinarians call acute or simple gastritis. Gastritis is usually caused by the ingestion of an irritant substance—for example, decomposed food, grass, paper, or bones. The cat often first vomits frothy clear or yellow fluid. Cats with gastric irritation may seek grass to eat in an attempt to disgorge any irritant or foreign material which remains, but grass eating is often an enjoyable pastime for cats and not a sign of illness.


Some cats vomit occasionally following meals. This type of vomiting is usually not serious in nature and may have several causes. Among the most common seem to be food gobbling, overeating, or a particular sensitivity to certain kinds of food.

If your cat is an after-meal vomiter, trying one or more of the following things may help you:

  1. If your cat eats with other animals, separate him or her at feeding time. Not only offer an individual food bowl but place the food bowls at a distance from one another. Competition encourages food gobbling.
  2. Feed smaller meals more frequently.
  3. Try a food that has to be chewed well before swallowing (e.g., large- sized dry kibbles instead of canned food).
  4. See if you can associate the vomiting with the kind of food being fed.

Some cats have food intolerances to certain ingredients in commercial foods, e.g., food colorings or flavorings. In such instances, you may find that only one brand or flavor of food seems to cause the vomiting. If you do find a specific food which seems to be the cause be sure to eliminate it entirely from your cat’s diet.


Cats with food allergies may also develop vomiting when fed certain foods, but the mechanism causing the vomiting is more complex than that of simple food intolerance. The immune system must react to the presence of the food allergen before any signs appear. The association with a specific food may be more difficult for you to make in these instances since the particular ingredient to which these cats are allergic must usually be withheld for several weeks to resolve the vomiting problem. Be sure to consult a veterinarian for diagnostic help if a simple diet change does not stop your cat’s signs.


Hairballs can also cause vomiting of a nonserious nature, but sometimes they cause serious obstructions and must be removed surgically. When hairballs are vomited they usually are tubular, brown masses and are emited by themselves or accompanied by a small amount of clear, foamy fluid. If you look closely at such masses or tease them apart you will find that they are composed primarily of hair. If you find vomited hairballs and your cat is acting normally you may assume that the current hairball problem is solved. This should alert you, however, to do something about hairball prevention to avoid future problems, as should stools that have a large amount of hair in them. A hairball problem can also cause lack of appetite or constipation.

Prevent hairballs by brushing your cat regularly, providing some insoluble fiber in his or her diet, and by the routine administration of commercial hairball prevention preparations available through your veterinarian or at pet stores. A fiber source cats enjoy is fresh grass. Grow wheat, rye, or oats in a pot and allow your cat to nibble them a few times a week. A home remedy for hairball prevention is mineral oil or white petrolatum. Other oils are not efficient hairball preventives because they are digested and absorbed by the cat. Add mineral oil at a rate of one teaspoonful per 10 pounds of body weight to the food once or twice a week for hairball prevention. (White petrolatum can be given directly by mouth.)


Vomiting cats may or may not be interested in their normal food. If your cat vomits once or twice, has no fever or obvious abdominal pain, and is no more than slightly depressed you can probably treat the vomiting at home. Do not feed your cat for twelve to twenty-four hours following vomiting. At the end of twelve hours (if you can’t stand to wait longer), you can offer a very small (about a tablespoonful) of soft, easily digested food such as a soft-boiled egg, meat baby food, or cottage cheese.

If your cat keeps this small meal down for about four hours, another small meal can be offered, then another about four hours later. If no further vomiting occurs, the next day’s meals can be normal-sized portions of bland food, and the following day you can return your cat to a regular diet. Water or other liquids should be offered frequently only in small amounts at a time to combat the tendency to dehydration that accompanies vomiting. Large amounts of food or water distend the already irritated stomach and usually cause vomiting to recur. An easy way to have water available in small portions is to place ice cubes in the water bowl. This allows the cat to drink the liquid that accumulates as the cubes melt.

Antacid liquids containing aluminum and/or magnesium hydroxide designed for humans may help soothe the irritated stomach lining. Dose aluminum or magnesium hydroxide antacids to provide 10 milligrams per pound (22 mg/kg) body weight every six hours until the signs have passed.

If vomiting is present with diarrhea (gastroenteritis) intestinal adsorbents are best. Do not give any preparations containing aspirin.


If your cat vomits more than a few times; if the vomitus is ejected extremely forcefully (projectile vomiting); if there is blood in the vomitus or obvious abdominal pain; if your cat seems particularly depressed, weak, or has a fever, or retches unproductively, do not attempt to treat the condition at home. Even simple gastritis cannot always be treated successfully without the help of a veterinarian, and there are many other serious causes of vomiting—among them foreign objects in the digestive tract, stomach ulcers, inflammation of the pancreas, panleukopenia, and kidney failure.

Expect your veterinarian to perform diagnostic tests such as complete blood counts, biochemical analysis of the blood, and radiographs (X-ray pictures) of the abdomen when the cause of vomiting is not immediately evident. Even more sophisticated tests are necessary in some cases, including endoscopic examination of the gastrointestinal tract and biopsy (removal of tissue for a pathologist’s examination.)