By Margie Scherk DVM, Dipl ABVP (Feline)
Vancouver, Canada


Casey is a 3-year old shorthaired cat who lives with her people in a small town in the United Kingdom. Her person, Janet, brings her to the veterinary surgery because Casey has vomited three times over night and three times during the morning. She was concerned because the vomit looked different than it normally does – there was no food and the liquid was frothy and green.

Wait! “Different than it normally does”? For some reason, it is believed that it is normal for cats to vomit. “It’s just what they do. It’s part of being a cat.” In fact, it is no more normal than it is for us. When cats (or people) vomit, it is a sign of a problem.

Lots of things make cats vomit – and that may be why we think it is “normal”. Everything from toxins (not just poisons, but also from bacteria, food or kidney disease) through stress or fear, motion sickness and, probably the majority of times, stimulation from an inflamed intestine (inflammatory bowel disease [IBD] or flu), stomach, liver, pancreas or heart. Why even an irritated colon (diarrhea) or stretched colon (constipation) can make cats vomit!

What to do? If kitty is well in other ways, the problem may be due to internal parasites or dental disease interfering with normal chewing. Cats with a painful mouth may even “binge and barf”. Please take your cat to see your veterinarian. As part of the thorough examination, she/he will check under your cat’s tongue for string (thread, tinsel, etc.). If no urgent problems are found on the physical exam, she/he may suggest switching to bland, readily digested food for a week. But if the problem persists or if your cat is acting ill, get her to the veterinarian quickly. Further workup, (blood tests and urinalysis, will be needed to sort things out. In fact, the cause for the vomiting, while often inside the GIT itself, may be due to systemic problems.

Please take note and make a list of what you are seeing at home. The more clues you can provide, the faster your kitty’s doctor can make headway in the diagnosis. Your vet will love you if you can tell her/him:

  • When did the vomiting first start?
  • How often does it happen?
  • Is the timing associated with eating? Does it occur right after eating or 4-8 hours afterwards? Or is there no relationship to the time of eating?
  • What does it look like (colour, quantity, consistency, contents)? Is it clear, colourless liquid or froth? Is it yellow or green? Is there fresh red blood or black coffee ground-like contents? Is it slimy or watery when you wipe it up? Are there worms in it? Does it smell like feces?
  • How much of it is there? (If a puddle, report in inches.) Liquid deposits on carpet make answering that question difficult, but if it is a pile, you can still report the size.
  • Can you see semi-digested food in it? What about hair, feathers, grass?
  • What does the process look like? (Get out your mobile phone and video it if you can.) Is it preceded by yowling, drooling, lip-smacking and repeated swallowing? If so, that suggests stomach and beyond. If the process looks less upsetting and the vomit is tubular, it may well be from the esophagus (regurgitation).
  • Did the problem started after or around the time of a change in diet? If so, that could cause an upset tummy or uncover a food hypersensitivity.
  • Has your cat been receiving any over-the-counter treatments, medications or homeopathic remedies? Please tell your vet.
  • Are any of your other cats sick? Infectious diseases that cause vomiting may also affect the other cats in the home making them feel unwell.

Remember to mention anything else that doesn’t seem normal with your kitty. Is there any diarrhea, weight loss, coughing, or increase in the amount of urine or drinking? In older cats, changes can occur gradually so you may have to think back 1 or 2 years and mentally compare current health to previous energy, temperament, appetite, weight, mobility, etc. In a younger cat, like Casey, changes in health tend to be more abrupt.

Cats who are unwell and have been vomiting for a while, will need to be rehydrated and have electrolyte imbalances corrected. X-rays or ultrasound may be indicated. The former, if a foreign body is suspected, such as Christmas tinsel, yarn or string, hair elastics or bones. These tend to be more common in younger cats but older cats sometimes get into trouble with eating things they shouldn’t, too.

Ultrasound is helpful to look for chronic inflammatory conditions (chronic enteropathies and IBD) and soft tissue obstructions including tumours, intussusception (which describes the bowel slipping over itself like socks turning inside out), or problems with adjacent organs. Ultrasound also allows for fine-needle samples or structures or fluid to be collected for evaluation. Based on the results of the tests, your vet might recommend surgery or endoscopy to remove a foreign body or to take biopsies, but most of the time that isn’t the case. Once certain that there isn’t something dire going on, your vet may suggest a therapeutic diet trial for IBD or antibiotics if they suspect a bacterial cause.

If the blood work shows that the vomiting is secondary to a problem outside of the gut, those problems will need treating. Examples of these include hyperthyroidism, chronic kidney disease, heartworm, diabetic ketoacidosis, liver or pancreatic diseases, cancer or diseases of the central nervous system.

For the many vomiting cats who don’t have underlying illness, a diet change (e.g., to a highly digestible diet, a novel protein diet, or a hydrolyzed protein diet) along with an antiemetic drug (to stop vomiting) may be all that is needed. If worms are seen, deworming may cure the problem. If there is dental disease, get that taken care of – kitty will feel so much better!

If there are hairballs (tubular wads of hair), in addition to using a petrolatum-based hairball remedy, a drug to improve gastric motility may be required. Other reasons for hair accumulations should also be considered (e.g., increased grooming related to stress, skin irritation, or localized pain).

Back to Casey. Because the vomit was green, she had a fever and was very lethargic, bloodwork and ultrasound were performed. These showed that she had severe pancreatitis that required intensive hospitalization for several days on intravenous fluids with medication to stop vomiting, provide relief from pain, and antibiotics. She’s back home and has recovered fully. 

Remember: vomiting always has a cause. Get it checked out.

"The trouble with cats is that they've got no tact"

P.G. Woodhouse