Merck Manual

Please confirm that you are a health care professional


Vomiting in Cats


Craig B. Webb

, PhD, DVM, DACVIM, Department of Clinical Sciences, Veterinary Teaching Hospital, Colorado State University

Topic Resources

Vomiting in cats is the forceful ejection of the contents (such as food or fluids) of the stomach and upper small intestine through the mouth. It is normally preceded by excessive salivation, repeated swallowing, retching, and forceful contractions of the abdominal muscles and the diaphragm. There are many causes of vomiting in cats. Vomiting can be caused by digestive system disease, kidney or liver failure, pancreatitis, or nervous system disorders. Some additional causes of vomiting include poisons, envenomation (for example, insect stings or snake bites), internal parasites (including heartworm disease), infections, inflammation, drugs, ingestion of a foreign object, food allergy, and tumors.

Managing Hairballs in Cats

As cats groom themselves they swallow some of the loose hair from their coat. Hair cannot be digested and tends to stick together in the stomach, where it forms into a lump or hairball (also called a trichobezoar). Often, cats will vomit up the hairball. In some cases, however, it remains in the stomach for a long time and hardens into a dense mass. This can irritate the stomach or even block the digestive tract. Longhaired breeds are at greater risk.

You can limit the amount of hair your cat swallows and help prevent hairballs from forming by frequently brushing your cat to remove loose fur. If necessary, medications, such as mineral oil, can be given to help cats pass hair through the digestive tract. Some commercial cat diets and treats are also formulated to help prevent formation of hairballs. In severe cases, surgery may be required to remove the hairball.

See your veterinarians if your cat is vomiting repeatedly. Something more serious than a hairball could be to blame.

Vomiting differs from regurgitation, which is a passive motion that does not require effort or contraction of the abdominal muscles. With regurgitation, the expelled food and fluid tends to be undigested and may have a cylindrical shape reflecting the shape of the esophagus. Coughing or difficulty breathing are more often associated with regurgitation than with vomiting.

Short-term or occasional vomiting is generally not associated with other abnormalities. Longterm vomiting may be associated with weakness, lethargy, weight loss, dehydration, and electrolyte (salt) imbalance. Whenever possible, control of vomiting is achieved by identifying and eliminating the cause while allowing the digestive system time to recover.

Short-term or Occasional Vomiting

When a cat has been vomiting occasionally for only a short time (less than 1 to 2 days) and no other signs of disease are present, your veterinarian may only need to provide supportive treatments to relieve signs. Generally, the treatment for short-term vomiting requires withholding food for 24 hours to allow the digestive system to rest. Water should only be withheld if your veterinarian provides fluid under the skin (subcutaneously) or by injection into the blood vessels (intravenously). Dehydration and other internal abnormalities are expected with vomiting, and withholding water can worsen these effects. Cats with kidney or heart disease may require a hospital stay with intravenous fluid treatment during this time. If the vomiting has stopped after 24 hours, the cat may be offered small amounts of water. If no further vomiting occurs, feeding can usually be resumed slowly.

Longterm or Severe Vomiting

Longterm vomiting, vomiting that occurs more often than once or twice daily, and vomiting accompanied by blood, abdominal pain, depression, dehydration, weakness, fever, weight loss, or other adverse signs requires a detailed examination by your veterinarian. Some causes of severe or longterm vomiting are life-threatening. Diagnosis may include blood, fecal, and urine tests as well as abdominal x-rays and ultrasonography. In many cases, endoscopic evaluation and biopsy of the stomach and small intestine are the only tests that can determine the cause of the vomiting.

The underlying cause of the vomiting needs to be treated. A cat with longterm or severe vomiting may also need to be treated for conditions such as dehydration, salt imbalances, and acid-base disorders that have developed. This may require a hospital stay with the administration of intravenous fluids. Drugs to control vomiting can be prescribed for animals with persistent vomiting, dehydration, and weakness.

For More Information

Also see professional content regarding vomiting.

Also of Interest