Cat Vomiting: Types, Causes, and Treatments

If you have cats, you’ve probably seen them throw up at one time or another. A cat vomiting is common, but it's never normal for healthy cats to do so. With that said, it's also not always something that has to be treated, nor do cats need to be rushed to a veterinarian every time they vomit. Get the scoop on when to take a vomiting cat to the vet, why cats vomit, and what treatments are available to help cats who are throwing up feel better.

Chronic and acute vomiting in cats

A cat throwing up can be separated into two broad categories: chronic and acute vomiting. Chronic vomiting means the cat is throwing up with some regularity (at least monthly but it can be daily) for a long period of time. The cat usually only vomits once or twice with each occurrence. When a cat who usually doesn’t vomit starts vomiting, that’s the acute type. This is generally a concern for you and your veterinarian only if the cat vomits multiple times. The diagnostic workup and treatments for acute and chronic vomiting can differ, as does the urgency of when to bring the cat to the veterinarian.

More urgent care is usually required for a cat with acute vomiting. The exception to this is a cat who has only vomited one to three times and is otherwise normal. If the cat still wants to eat and does so without continuing to vomit, is acting normal, and seems comfortable, then the cat likely doesn't need to be brought to a veterinary hospital unless you know the cat ate something toxic. 

If your cat vomits more than three times, cannot keep food down, and seems tired, they should be seen by a vet as soon as possible. They might just be experiencing some passing nausea, but if it’s something more serious, treatment should be implemented as soon as possible. Unless the cat is in severe discomfort or does not want to move, they normally won’t have to go to an emergency clinic. But if the cat seems to deteriorate quickly through the night, then an emergency visit is recommended. Cats who are continuously vomiting and not keeping food down are prone to many secondary changes, most notably liver disease, so waiting to get treatment can be dangerous for them.

A chronically vomiting cat should still be seen by a veterinarian. But it’s not urgent if the cat is still eating and keeping food down, is not showing signs of weakness, and seems comfortable. If these things are not true, a chronically vomiting cat is either an acutely vomiting cat or is having an acute crisis of whatever is causing the chronic vomiting. 

In the past, a cat who vomited a few times a month was considered normal, but that idea is changing. There is even some thought that a cat who frequently vomits hairballs might have some gastrointestinal disease that does not allow the hairballs to pass normally. A treatment might not be implemented for a chronically vomiting cat, but an exam and a workup should be done to ensure that the cat is comfortable and does not need any intervention at that time. 

Causes of vomiting in cats

The causes of acute or chronic vomiting can be the same, but there are exceptions. Toxins are generally not a cause of chronic vomiting (unless a cat is chronically exposed to the same toxin, such as eating a toxic plant). Ingesting a foreign body (typically string) is not normally a cause of chronic vomiting — although if the foreign object remains in the stomach, it can be a cause of chronic vomiting.

Unfortunately, vomiting is a very vague symptom, and the causes are extremely varied. In fact, almost any feline illness can result in vomiting. In general, the causes of vomiting can be placed in one of these categories: toxins, drugs, diet (including eating inappropriate things), gastric (stomach), intestinal, organ dysfunction, endocrine, neurologic (typically brain-related), infectious, and cancer. 

In each of these categories are dozens of specific diseases and syndromes. Some of the more common causes are:

• Toxins: Lilies, antifreeze
• Drugs: Chemotherapy, antibiotics, anti-inflammatories
• Diet: Dietary intolerance to something in food, sudden change in diet, eating a dead thing
• Gastric: Foreign bodies, ulcers, inflammation of the stomach
• Intestinal: Foreign bodies, acute inflammation, inflammatory bowel disease (more typically chronic), cancer, constipation
• Organ dysfunction: Liver disease, kidney disease, pancreatitis
• Endocrine: Hyperthyroidism (overactive thyroid gland), elevated calcium, diabetes ketoacidosis
• Neurologic: Vestibular disease (can be associated with inner ear disease), encephalitis (inflammation of the lining of the brain), cancers
• Infectious: Feline infectious peritonitis, feline panleukopenia, heartworm
• Cancer: Can be a direct cause, such as intestinal cancer, or an indirect cause, such as mast cell tumors in the skin

Diagnosing the cause of vomiting

It can be difficult to diagnose the cause of vomiting in a cat. Most cases of acute vomiting are transient and improve with just symptomatic therapy and time. However, a basic workup is often recommended to ensure that a more serious problem is not going on. 

The starting point in determining the cause of vomiting is getting an accurate history. Here are some questions your vet might have:

• Was the cat exposed to plants and other toxins? 
• When did the vomiting start?
• What is the cat’s normal diet?
• Does the cat go outside, and if so does the cat hunt? 
• What is in the vomit?
• Is the cat on medication?
• Is there also diarrhea?
• Is the cat eating?
• When does the vomiting occur (in relation to eating or other activities)?
• Is the cat losing weight?
• Is the cat drinking a lot or urinating a lot?
• Does the cat play with string? 

Based on the answers to these questions, your veterinarian will have a better idea of which diagnostics, if any, to use. 

What the vomit looks like does not give a definitive answer about why the cat is vomiting, but it can give the vet a place to begin looking. Though by no means a perfect correlation, the following vomit characteristics can offer some clues:

• Yellow vomit: This is bile and can be a sign of liver disease, but it often occurs with an empty stomach. It can also mean the cat ate something yellow.
• Clear vomit: This can be regurgitation from the esophagus or from an empty stomach.
• White, foamy vomit: Again, this is typically regurgitation from the esophagus or from an empty stomach.
• Blood in the vomit: The blood is from the mouth, esophagus, or stomach.
• Coffee-ground appearance to the vomit: This type is from bleeding from the stomach, most commonly seen with ulcers.
• Brown, smelly vomit: This can be from bleeding in the upper gastrointestinal tract or from having eaten something brown and smelly.
• Undigested food in the vomit: This means that the food never left the stomach. It can happen with food intolerances or allergies, obstructions, or pretty much anything that causes upper gastrointestinal tract irritation. It is important to know when the cat last ate. For instance, if the cat has not eaten for a day and is vomiting undigested food, that would point to an obstruction or a motility disorder.

Veterinarian examination and testing

The next step is a thorough physical exam by your veterinarian. The veterinarian can look for things such as abdominal pain, masses in the abdomen or elsewhere, an obvious foreign body (such as a string under the tongue), evidence of weight loss, a heart murmur, an enlarged thyroid gland, and a fever. Again, the exam can help determine which, if any, diagnostics are needed.

Abdominal X-rays and blood work

If warranted, the initial tests are usually abdominal radiographs (aka X-rays) and blood work with a urinalysis. X-rays can reveal abnormalities in organ size and shape, foreign bodies, tumors, constipation, and other abnormalities that the vet might not be able to assess with a physical exam. Blood work can detect things like organ dysfunction and can diagnose endocrine disorders like diabetes and hyperthyroidism. A urinalysis is needed in conjunction with blood work to diagnose conditions like diabetes, kidney disease and urinary tract infections.

Blood work can also give clues about whether an animal has been exposed to some toxins, such as antifreeze. Unfortunately, there are not many easy tests to diagnose toxin exposure. It is often required that the cat’s person knows of potential exposure to the toxin and the presence of classic signs of toxin exposure.

Barium study, ultrasound, and endoscopy

Often, X-rays do not diagnose the problem (other than the presence of foreign bodies and a few other conditions), but they help determine whether further abdominal studies are needed. These other studies could include a barium study, which will help determine whether there are foreign objects in the intestines or whether there are motility issues with the intestines. Another study could be an ultrasound to look at the architecture of different organs; ultrasound can be used as a means to sample different organs to get a definitive diagnosis.

In addition, an endoscopy (using a scope to look into the stomach, upper intestines, or colon) might be recommended by your vet. Endoscopy is a way to look for foreign objects in the stomach that do not show up on X-rays, and it can be used to retrieve foreign objects. This procedure also allows viewing of the lining of the stomach and upper intestines to look for abnormalities, and it can be used to collect samples of the upper gastrointestinal tract.

Exploratory surgery

In a cat with persistent vomiting that is not being controlled by symptomatic therapy, exploratory surgery might be needed. This is true with some acute vomiting situations (namely, concern that a foreign body is present) and some chronic vomiting situations (namely, looking for signs of intestinal cancer, non-intestinal abdominal disease, or inflammatory bowel disease).

In the case of foreign objects, the surgery is used both to diagnose and fix the problem by removing the foreign object. If no foreign object is found, then biopsies can be taken during the surgery. The intent of doing a surgery for chronic vomiting is normally to take biopsies of the intestines, stomach, liver, pancreas, lymph nodes, and any abnormalities in the hope of diagnosing the problem. The most common things to diagnose are inflammatory bowel disease or a form of cancer.

As a diagnostic tool, surgery is preferred over endoscopy by some veterinarians because the whole intestinal tract can be evaluated, as well as different organs in the abdomen. In addition, full thickness and larger intestinal biopsies can be taken during surgery. Furthermore, biopsies of the liver, pancreas, and lymph nodes can be taken. 

Conversely, endoscopy might be preferred because it is usually less expensive (although not by much), usually results in a representative sample of the intestines to provide a diagnosis, and is much less invasive. It can take several weeks for a cat to recover from surgery, while an animal who has had an endoscopy and endoscopic biopsies usually recovers within a few hours or within a day.

Because some of the diagnostics can be invasive and expensive (endoscopy can run up to $1,500 and exploratory surgery can cost more than $2,000), many people elect not to do them. There are treatments that can be implemented without a full diagnosis, but those decisions will require communication between you and your veterinarian about the risks of doing those treatments.

Treatments for a cat who’s throwing up

The treatment for vomiting varies greatly based on the cause, and describing the treatment for each individual cause is beyond the scope of this resource. However, we can give some generalizations for treatment. 

Fluids

If the physical exam reveals no abnormalities and nothing in the cat’s history raises a red flag, a veterinarian might just elect to do some symptomatic therapy, such as administering fluids subcutaneously (under the skin). Even if an animal is not clinically dehydrated, giving fluids can be important to flush the system and to maintain hydration. A vomiting patient is likely a little dehydrated simply from fluid loss from vomiting and failure to keep water down.

Dehydration is a self-perpetuating problem, meaning that when animals are dehydrated, they don't feel good and therefore won't eat or drink and might even vomit more. This makes them more dehydrated, which makes them feel worse and less likely to eat or drink — and then they get more dehydrated.

Some form of fluid therapy is given for almost every cause of vomiting. If an animal is very dehydrated or weak, IV fluids are often recommended. This involves placing a catheter in a vein and giving the animal fluids through the catheter. It’s a more direct way to give fluids, and more fluids can be given via this method throughout the day. The downside is that giving IV fluids is significantly more expensive and requires the cat to stay in the hospital. However, especially in a very dehydrated patient, subcutaneous fluids do not absorb very well and IV fluids are needed to help the cat.

Anti-vomiting medication

Another common therapy for most kinds of vomiting is giving an anti-emetic (anti-vomiting) medication, which can help stop the vomiting and thus decrease fluid loss. These medicines can also help relieve abdominal discomfort and make the cat more prone to eating. Sometimes, stomach protectants such as Pepcid or sucralfate might be indicated, but the helpfulness of these is up for debate. They typically do not cause any harm though. If the anti-emetics do not provide adequate pain control, a pain medication might be added to the cat’s treatment plan.

Diet changes

For both chronic and acutely vomiting cats, one of the most important treatments is dietary change. If your cat has an acute case of vomiting, this might involve a temporary change to an easily digestible diet, such as Royal Canin Gastrointestinal High Energy cat food, Hill’s ID cat food, or a bland human food such as meat-flavored baby food (with no onion or garlic powder added) or boiled chicken. Keep in mind that chicken and baby foods are not complete diets for cats and therefore should only be used for a few days. For cats with chronic vomiting, a diet change can be therapeutic as well as diagnostic.

If the new food controls the vomiting, it was partially caused by a dietary intolerance or allergy or possibly low-grade inflammatory bowel disease. Regarding diet trials for chronically vomiting cats, keep them on the new diet for several weeks to see whether it is working. The cat should be on one of the aforementioned prescription diets or a limited-ingredient prescription diet to make sure it’s a complete, balanced diet.

Prednisone 

Inflammatory bowel disease might be the cause of vomiting in some cats. The treatment for inflammatory bowel disease often involves the medication prednisone. We don’t recommend that you try prednisone on your cat without any diagnostics being done because prednisone has a lot of side effects, including an increase in thirst, an increase in urination, a weaker immune system, and weak muscles. Giving a cat prednisone can also make some causes of vomiting (such as pancreatitis, diabetes, and kidney disease) worse. However, if your cat’s blood work and X-rays are normal and you do not wish to pursue further diagnostics, a trial of prednisone could be considered. You’ll want to have a thorough discussion with your veterinarian about the risks.