Why Is My Cat Throwing Up?

A cat throwing up now and then is common, and a hairball is often the reason. Cornell's Feline Health Center advises a prompt vet visit if she vomits more than once a week.

The same goes if vomiting comes with tiredness, weakness, a poor appetite, blood, more thirst, peeing changes or diarrhea.

One quiet episode in a cat who then eats, plays and acts like herself is usually not an emergency. Repeated vomiting, or vomiting with any of those signs, needs a vet.

Below is how to tell what you're looking at, what usually causes it, and exactly when to pick up the phone.

Is it normal for a cat to throw up?

Occasionally, yes. Cornell puts it plainly: even the healthiest cat is apt to vomit now and then, and often there's nothing to worry about beyond the cleanup.

Hairballs are the classic example. Cornell notes it is not uncommon for a cat to bring up a hairball once every week or two without any lasting problems.

Not every vet agrees. A 2013 review in the Journal of Feline Medicine and Surgery found hairball vomiting in around 10% of otherwise healthy shorthaired cats. Its author argues that frequent hairballs in most shorthaired cats point to an underlying chronic problem.

The editorial that ran alongside it lands in the middle. Hairball vomiting can be normal, or a sign of digestive disease. What matters is a change in the pattern or frequency, and other signs such as weight loss or a change in appetite.

So the useful question is less "is this normal?" and more "is this normal for my cat?" A cat who brings up a hairball every few weeks for years is in a different place from one who has suddenly started vomiting most days.

Is it a hairball, vomit or something else?

What you saw, and how it came up, tells your vet a lot. The Merck Veterinary Manual separates two things that look alike on the carpet.

What happened	What it looks like
Vomiting	Active and forceful. Usually drooling, repeated swallowing and retching first, with the belly heaving.
Regurgitation	Passive, with no heaving. Food comes up undigested and may be tube-shaped, like the esophagus.
Hairball	A damp wad of hair, usually about an inch long, colored like her coat and darkened by bile.

Here's a detail that surprises people. Cornell describes hairballs as slender and cylindrical, shaped more like a cigar or sausage than a ball. They can reach five inches long.

A cough can fool you too. Owners often say a cat is "coughing up" a hairball, and the 2013 review notes that vets must ask careful questions to tell a chronic cough from frequent hairballs.

If your cat crouches and hacks but nothing comes up, mention it to your vet.

What makes cats throw up?

The list is long, which is why a vet starts with questions before tests. Cornell groups the common causes like this.

• Hairballs, usually the most harmless cause.
• Something she ate: leaves of poisonous plants, spoiled cat food, human medicines, string or yarn, antifreeze, or human foods such as chocolate and onions.
• Small objects found on the floor, such as paper clips and rubber bands.
• Internal parasites.
• Digestive conditions such as constipation and inflammatory bowel disease, or a blockage from a swallowed object.
• Growths in the digestive tract, both benign and cancerous.
• Metabolic diseases, including diabetes, kidney disease and hyperthyroidism.

That last group is the reason repeat vomiting deserves a proper look. Cornell calls inflammatory bowel disease a common disorder in cats, and none of these can be ruled out at home.

Why string is different

String, thread, yarn and dental floss are a special danger. Merck explains that one end can catch under the tongue or in the stomach while the rest is pulled along the intestines, which bunch up around it.

If you see string in your cat's mouth or under her tongue, never pull it. Merck warns that pulling can tear the tissue. Call your vet right away.

Holiday tinsel and ribbon carry the same risk, which is one reason to cat-proof a Christmas tree before December.

What about cats who eat grass?

Plant eating is far more common than most people expect. In a 2021 survey of more than 1,800 cat owners, published in the journal Animals, 65% of the cats ate plants weekly.

Only 6% looked ill beforehand, and 37% frequently vomited afterward. Short-haired cats ate plants as often as long-haired cats, so the authors concluded grass eating is probably not a way to clear hairballs.

Grass is one thing. Many houseplants are toxic to cats, so check any plant against the ASPCA's toxic plant list before it comes indoors.

When should I take my cat to the vet for vomiting?

This is the part to keep. The thresholds below come from Cornell and the Merck Veterinary Manual.

Call your vet promptly if your cat:

• vomits more than once a week, even if she seems fine otherwise
• vomits more than once or twice in a day, or keeps vomiting for more than a day or two
• seems tired, weak or depressed
• eats less than usual, or refuses food for more than a day or two
• has blood in the vomit
• is drinking more, or peeing more or less, than usual
• has diarrhea at the same time
• is losing weight, or has a fever or seems dehydrated
• keeps retching without bringing anything up

Go now, as an emergency, if:

• there is blood in the vomit, or her belly seems painful
• you see string or thread in her mouth, or think she swallowed some
• she may have eaten something toxic, such as a lily, a human medicine or antifreeze

For a suspected poisoning, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435. It is staffed around the clock, and a consultation fee may apply.

Merck notes that vomiting lasting less than a day or two, with no other signs, may only need supportive care. Even then, your vet is the right person to decide that.

What can I do at home right now?

If your cat has thrown up once and otherwise seems herself, a few calm steps help.

1. Keep fresh water available. Merck warns that withholding water makes dehydration worse, unless your vet is giving fluids. Our guide to cat hydration has simple ways to encourage drinking.
2. Ask your vet before you hold back food. Merck's owner guide describes resting the stomach for a day, but Cornell counts refusing food for more than a day or two as a reason to see a vet.
3. Don't give any human medicine. Cornell lists human medications among the common causes of vomiting in cats.
4. Look for the cause. Check for chewed plants, string, hair ties or an open bin.
5. Write down what you saw. Note when it happened, what came up, and whether she heaved or it simply slid out.

That last step is worth the effort. Cornell explains that working out the cause of frequent vomiting begins with a thorough history from the owner, before any bloodwork or x-rays.

Can I cut down on hairballs?

Often, yes. Hairballs start with grooming, and cats groom a lot. The 2013 review cites research finding grooming takes up around 25% of a cat's waking hours.

Most of the swallowed fur passes through in the stool. The rest can collect in the stomach. Frequent hairballs are about twice as common in longhaired cats as in shorthaired ones, the review found.

• Brush and comb daily. Cornell recommends it, especially for long-haired breeds such as Persians and Maine Coons. Our guide to choosing a cat brush covers which tools suit which coat.
• Watch for heavy licking or scratching. The review names itchy skin, fleas and food intolerance as common contributors to frequent hairballs.
• Skip the home laxatives. Cornell says never to give them without your vet's approval and supervision.

The reason to take hairballs seriously is rare but real. Cornell warns that a hairball lodged in the small intestine can be fatal without surgery. Lethargy, refusing food, or repeated unproductive retching are the signs to act on.

Questions cat parents ask

Is it normal for a cat to throw up once a week?

It's right at the line. Cornell advises a prompt vet visit for any cat vomiting more often than once a week, so a weekly habit is worth raising at her next appointment, sooner if it increases.

Why is my cat throwing up right after eating?

If food slides out undigested with no heaving, that's regurgitation, which Merck separates from true vomiting. If it keeps happening, tell your vet which one you saw.

Why is my cat throwing up hairballs so often?

Long coats and heavy grooming play a part. In shorthaired cats especially, frequent hairballs can point to itchy skin, fleas or a digestive problem, so ask your vet.

Should I stop my cat eating grass?

Research suggests plant eating is a normal behavior, and most cats seem well beforehand. Keep toxic houseplants out of reach, and lilies out of the house entirely.

Sources

• Cornell Feline Health Center: Vomiting
• Cornell Feline Health Center: The Danger of Hairballs
• Merck Veterinary Manual: Vomiting in Cats
• Merck Veterinary Manual: Gastrointestinal Obstruction in Small Animals
• Cannon M. Hair balls in cats: a normal nuisance or a sign that something is wrong? Journal of Feline Medicine and Surgery, 2013
• German AJ, German AC. Bad hair day. Journal of Feline Medicine and Surgery, 2013
• Hart BL, Hart LA, Thigpen AP, Willits NH. Characteristics of Plant Eating in Domestic Cats. Animals, 2021
• ASPCA Animal Poison Control Center

This article is for general information and is not veterinary advice. Talk to your vet about your own cat — they know the animal in front of them.

Choolip products are food supplements, not medicine. They are not intended to diagnose or manage any medical condition. If your cat has been diagnosed with a condition, their diet should be set by your vet.