As any cat owner knows, cats frequently vomit. What causes cat vomiting, however, is not always so easily determined.

The normal, healthy cat may routinely vomit once or twice a week as a rule, without any obvious medical reason. In most cases, cats that vomit occasionally without any other sign of illness are either doing so due to their eating habits, or due to hairballs.

What causes cat vomiting in animals that have just eaten is usually not vomiting at all, but regurgitation. This is most commonly seen with cats who eat very quickly, and those who eat an exclusively dry food diet. When ingested, dry food will absorb the moisture in the cats stomach, expanding in size, encouraging the cat to regurgitate to alleviate discomfort. By soaking dry food before feeding it to your cat, or by dividing the food into smaller meals more frequently during the day, you can help to solve this problem.

Cats are excellent self-groomers, but an unfortunate byproduct of their good hygiene is hairballs. The unique structure of the cats’ tongue stems from the presence of small papillae on the surface of the tongue, acting like a comb as the cat grooms itself. Hairs “combed” are then swallowed, and this indigestible material stays in the stomach, accumulating more hair as well as other food material. Eventually the hairball becomes irritating and begins to interfere with eating and drinking, at which point the cat will cough, hack, retch, and hopefully, vomit up the offending hairball. Most prevalent in long-haired cats, a dry cough and frequent retching, especially after meals, as well as small spots of yellow bile on the floor or carpet, are evidence of unsuccessful attempts to void the hairball. Once successful, the final result is a disgusting wet and sticky mass of hair on your floor.

Brushing your cat can significantly reduce his development of hairballs. Commercial hairball remedies are available to help the hairball pass in the feces, but will not prevent hairball formation.

In cats that vomit intermittently, parasites may be playing a role. Giardia, an intestinal parasite that is caused by a single-celled organism, is highly prevalent in catteries and shelters, and is easily passed from cat to cat via infected soil and water. Salmonella, a bacterial infection, as well as intestinal parasites such as roundworms and tapeworms can cause intermittent vomiting as well as diarrhea in cats. Many affected cats will appear healthy, except for short bouts of intestinal upset, and some may show no outward signs at all, but still harbor a parasite.

Fecal screening can determine the presence of intestinal parasites, and medication is available to treat and cure this cause of cat vomiting.

Older cats that begin vomiting more frequently later in life may be experiencing a more serious medical problem.

Chronic vomiting (occurring more than twice a week for at least 3 weeks) in older cats is often caused by irritable bowel disorder, or IBD. This disease of the gastrointestinal tract causes increased inflammatory cells, which can affect the mucosa of the small intestine (enteritis), large intestine (colitis), stomach (gastritis), and colon.

There are many potential causes of IBD, but the specific cause in each case is generally not known. The most common causes include food allergies or sensitivity to certain types of food, bacteria in the intestinal tract, and as well as immune system disorders.

While IBD is itself a painful and troublesome condition in cats, untreated it can lead to potentially fatal complications. The chronic inflammation has been found to lead to scaring in the mucosa of the digestive tract, and lymphoma has found to develop as a result of the chronic irritation and scaring.

Kidney disease and renal failure occur in a great number of older cats, and is one of the leading causes of death in cats. The kidneys are the filtration system of the body, filtering waste products from the blood, and expelling them through the urine. Over time, kidneys can begin to degrade and their function decreases. This process typically occurs over a long period of time, and because the kidneys can continue to function normally even with up to 70% of their function lost, by the time symptoms are present the disease is often quite advanced. Weight loss is the most common symptom of kidney failure, but affected cats may also have symptoms of vomiting, decreased appetite and depression. Blood tests can diagnose kidney failure, and treatment is aimed at reducing the workload of the kidneys by increasing fluid intake, and feeding a diet specially formulated for kidney failure.

Another common disease of older cats is hyperthyroidism, or an overactive thyroid gland. Thyroid hormones control metabolism, and when that hormone is increased it can adversely affect many of the cats body systems. Hyperthyroid cats often have weight loss despite an increased appetite, rapid heart rate, vomiting, diarrhea, increased blood pressure and behavioral changes. Hyperthyroidism is often easily controlled with daily medications, as well as frequent bloodwork to assess other body systems and monitor thyroid levels.

Any time a kitten has any repeated episode of vomiting is cause for concern. Kittens are especially vulnerable to Feline Panleukopenia, or feline distemper, a highly contagious disease. Common in shelters, catteries and boarding facilities, this virus can be deadly in kittens, and cause fever, vomiting, diarrhea and dehydration in cats of all ages. Vaccination is the best way to prevent infection.

While chronic renal failure most often occurs in older cats, a sudden onset of vomiting in cats can be a sign of acute renal failure. A life-threatening emergency, acute renal failure can be caused by severe kidney infections, ingestion of substance toxic to the kidneys (i.e. poison ingestion), or kidney obstruction. Symptoms of acute renal failure include sudden, acute vomiting, lethargy, weakness, disorientation and ataxia (poor coordination). Immediate, intensive medical treatment is required to treat the underlying cause of the kidney malfunction, and to support the body as the kidneys recover. Intravenous fluids and even dialysis may be performed to clear your cats body of toxins, and return function to the kidneys.

What causes cat vomiting can be a tricky thing to determine. Regular examinations with your veterinarian, as well as attention to your cats normal routine can help to determine when vomiting is normal, or not normal, for your cat.