What Are the Causes of a Cat Not Eating and Vomiting?

Occasional vomiting (once every few weeks) and not eating is normal in healthy, happy cats who are otherwise active, alert, playful and who eat and drink well. However, if either the vomiting or fasting is persistent or prolonged, a vet trip is warranted to rule out sickness or health issues. The two symptoms don’t usually appear together, so if your cat is vomiting and not eating, he probably has medical problems that a vet should evaluate.

  1. Vomiting in Otherwise Healthy Cats

    • Ingesting a field mouse can cause a cat to vomit.

      Hairballs are probably the most frequent cause of vomiting in a healthy cat, although Dr. Mary Ashley Waikart, DVM from Ventura, California insists that hairball expulsion should happen only three to four times a year.

      Cats can have an intolerance to food additives or sensitivity to certain foods like chicken, milk, eggs, fish or cereals. Waikart says that allergies are usually to protein, and the fix can be as simple as changing from chicken or beef to fish or vice versa.

      Cats can regurgitate food they aren't used to or food that’s too rich for them. If kitty swallows a whole bird or mouse, it can get caught in her esophagus and cause her to regurgitate. Cats can vomit if they scarf down their food too quickly.

      Daily vomiting can mean your kitty is nibbling on cat-toxic houseplants behind your back. “All types of lilies are fatal,” Waikart cautions. Cats can also get into household cleaners or ingest toxic chemicals by licking paws after walking through treated floors or carpets. Although kitty will try to upchuck the toxin, she’ll often need professional help to counteract the poisons.

    Not Eating

    • I said I wouldn't eat that food again!

      Stress is as hard on cats as it is on people. Some cats stop eating if their surroundings get noisy or busy, because they feel a need to be on watch and on guard. If you have more than one, a cat might stop eating if he feels intimidated by a bullying or overactive sibling. Strangers can also put kitty off his food.

      Cats will often not eat if they don’t feel well. For instance, cat bites can inflame and turn into abscesses, which are painful enough to put kitty off his food. Fevers, aches and pains, especially from arthritis, can cause kitty to lose his appetite.

      If a cat suddenly refuses to eat his normal fare, it may be that he’s bored with the same old food.

      Waikart warns that if an overweight cat stops eating for even one day, it’s important to seek help immediately. It’s common for overweight cats to have hepatic lipidosis, widely known as fatty liver disease. This is where fat clogs up the liver because too much fat has been metabolized and stored.

    Vomiting and Not Eating

    • Loss of appetite and vomiting are symptoms of illness a vet can treat.

      Hyperthyroidism (overactive thyroid gland) is the number one cause of vomiting in older cats, according to Dr. Waikart. It presents as weight loss with increased appetite at the same time.

      Food allergies trigger an inflammation of the stomach lining which causes kitty to expel the irritant. Chronic inflammation is known as Inflammatory Bowel Disease, IBD, and may distress kitty enough not to eat.

      Undigested pieces in vomit that occur a couple of hours after eating can signal renal problems. According to Waikart, kidneys often give out in older cats around the age of 15.

      Finally, if kitty vomits or doesn’t eat, he may have a tumor or obstruction in his intestines that is not caused by something he ate.