Inflammatory Bowel Disease In Your Cat

Feline Chronic Diarrhea And Vomiting

Ron Hines DVM PhD

If your pet is a dog   

Read about triad disease as well 

Also this one on lymphoma 

Check cats with persistently loose stools for Tritrichomonas  

 Nothing  helping? Consider a home-prepared diet   

  Why might my cat have this problem?   

I borrowed this introductory paragraph from my article on IBD in dogs. That is because I believe that similar intestinal problems have similar causes. Inflammatory bowel disease (IBD) is not one disease, it is many – a catch-all term veterinarians and physicians use to describe many conditions with similar signs but very different primary causes and presentations. That is why one treatment plan is never appropriate for the entire panorama of cats that deal with IBD-like issues. Current thought  among research physician is that many cases of IBD (and crohns disease) are the result of an immune system error involving CD8+ TRM  lymphocytes, one of a subset of the defensive cells of the immune system. ( read about that here  & here ) The theory is that the ones that reside in the walls of the intestines (tissue resident CD8 T cells) have mistaking harmless bacteria residing in the colon for dangerous pathogens that need to be destroyed. To hasten bacterial destruction, these cells release inflammatory cytokines.

What is Inflammatory Bowel Disease?

It is quite common for cats to occasionally vomit or have diarrhea. In longer haired cats, it is often associated with hairballs. In shorter haired cats it can be due to eating new foods. But when cats vomit too frequently, they have a medical problem. One of the common causes of these problems is inflammatory bowel disease (IBD). If you have reached this page and are not sure that your cat’s diarrhea problem is chronic, go here.

In cats, IBD is due to long term irritation and inflammation of your cats digestive tract. Whether your cat vomits, has diarrhea or both, depends on which part of the tract is most inflamed. When it is the colon that is most affected, it is sometimes just called colitis.

Inflammatory Bowel Disease can start at almost any age. But most cats that visit the vet for the first time with this problem are six or seven years old. Purebred cats may be slightly more prone to the problem.

We are uncertain as to the cause, but in certain situations, the cat’s body zeros in on a problem in its digestive tract. It acts as if it had been invaded by a disease organism and sends defense cells  to the area to fight the perceived infection. These cells release substances that inflame the stomach and intestines, causing them to thicken with increased blood flow and fluid. Inflamed intestines are spastic (hypermotile) and sensitive. This is the cause of the vomiting and diarrhea you see. In this condition, your pet’s intestines can not absorb food nutrients well, which can cause weight loss and decreased appetite. If the problem is worst high in the intestine and stomach, cats tend to vomit more. Those in which the mid portion is most affected tend to have more watery diarrhea and weight loss. Those in which the final portion of the intestine (colon) is most affected often have mucousy loose stools, sometimes with specks of blood and straining. Straining cats look alike, so it is hard for owners to tell if this last group are straining to poop, pee or if they might be constipated. Although one portion of the digestive tract is affected more than another, most cats have some degree of inflammation throughout their digestive tract.

Inflammatory Bowel Syndrome is not the same as Irritable Bowel Syndrome . In Irritable Bowel Syndrome, it is the nerve supply to the intestines that is causing the hypermotility. The usual cause of this is stress – similar to the condition of the same name that affects humans. (ref) IBD in cats can be just as frustrating to control.

What Happens In Inflammatory Bowel Disease?

The immune system is a very complex system. It must be able to tell the difference between things that belong in your body and things that might pose a threat to your body. Sometimes it makes a mistake and attacks parts of its own body. This is what happens in people with lupus, rheumatoid arthritis, juvenile diabetes and some aplastic anemias.

Basically, in IBD, the body’s army of defensive cells is rushing to meet an enemy in the intestine that is really not there. Or, at least, it is an enemy veterinarians haven’t yet discovered. These defensive cells are neutrophils, lymphocytes , plasma cells macrophages and eosinophils. Each concentrates on a particular form of invader. Gathered in the walls of the cat’s intestines, they release chemicals that damage the lining and wall.

In the most common form of IBD in cats, pathologists see mostly lymphocytes and plasma cells in the intestinal and stomach wall. So this form is called Lymphocytic-plasmacytic or lymphoplasmacytic IBD. In the second most common form, eosinophils predominate. This is called eosinophilic IBD. A third form, granulomatous IBD, describes the pattern that excess macrophages form in the tissue.

What Signs Might I See If My Cat Has Inflammatory Bowel Disease?

Often the first hint of a problem is whey your pet starts pooping outside of it’s litter box. Symptoms of IBD come on very gradually, so the stools may look fairly well formed to begin with. But with time, they are obviously too loose or watery. The problems tend to begin in spurts and things may return to normal for a while. Vomiting is also common and most owners assume at first that the problem is hairballs.

Inflammatory Bowel Disease is a progressive problem. It gets worse as time goes by. Vomiting and diarrhea become more persistent and the cats may lose weight. Some cats lose their appetite, while others become more hungry. Inflamed lower intestines bleed, so mucus, straining and flecks of bright blood may be present on the cat’s stool. When the majority of the pathology is higher up the digestive tract (closer to the stomach), cats usually pass very large stools with little or no discomfort, no straining, no bright blood and little or no mucus.

Because the cat’s pancreas and gall bladder are located close to the small intestine, underlying IBD may affect them as well. The combination of intestinal inflammation, pancreatic inflammation and, sometimes, liver/gallbladder inflammation are called triaditis. Read about that condition on this website and as a research article here. Cats with this multiple problem my turn yellow with jaundice and become severely ill.

WHAT Are The Causes Of Inflammatory Bowel Disease In Cats?

Veterinarians do not know why some cats develop this problem. IBD is probably a group of diseases with similar symptoms but a variety of causes. Like a complex computer program, anything that causes your cat’s immune system to make an error and get out of whack is a possible cause. Scientists and veterinarians speculate that perhaps sensitivities to food ingredients, the chemical products of harmless intestinal bacteria, or toxins in the pet’s environment could all be responsible. The high carbohydrate/grain content of most commercial cat foods may also be involved. You can read a bit about that here.

How Will My Veterinarian Know For Sure If My Cat Has Inflammatory Bowel Disease?

When your mature cat suffers from chronic diarrhea, and/or vomiting, IBD is always a possible cause. Since the tests that positively identify IBD are complicated and expensive, veterinarians tend to eliminate other possible causes first. There is nothing specific cat owners can do at home be certain the problems is IBD. Most unimportant causes of vomiting and diarrhea pass within a weeks or so with or without treatment. When they don’t, or when your pet is noticeably ill, it is time to take the cat to your veterinarian for diagnosis.

Are There Other Health Conditions That Could Be Mistaken For IBD?


A number of other health problems can cause your cat to vomit and have diarrhea. Your veterinarian will sort through them. Hyperthyroidism can cause signs similar to IBD. So can kidney failure, pancreatitis, food allergies, intestinal parasites, intestinal tumors, and bacterial infections. Feline leukemia and Feline AIDS can also cause similar signs.

What Tests Will My Veterinarian Suggest?

A physical examination of your cat is important. Sometimes your veterinarian can feel that your cat’s intestines are thicker and firmer than they should be or that the lymph nodes that surround them are larger than they should be.

Your veterinarian will examine a stool specimen from your cat. The vet will be looking for parasites and qualities of the stool that tell how well digestion is occurring.

If nothing abnormal is found, the vet will order some blood tests. There are no specific results that tell your veterinarian that IBD is the problem, but the tests let other conditions be ruled out.

Depending on the results, the vet may suggest an x-ray or ultrasound examination of your cat’s abdomen to check for possible intestinal motility problems (megacolon ). Chronic constipation problems and a resulting ballooning of the cat’s large intestine (megacolon) are quite common conditions. Cats with megacolon often have bouts of diarrhea and vomiting as well as constipation that looks quite similar to IBD. So x-rays and an ultrasound examination of your cat’s intestines may be part of the work up.

Your vet may suggest some diet changes to rule out a specific food allergy.

Your veterinarian will examine a stool specimen from your cat to check for intestinal parasites.

The veterinarian may send out a stool culture to rule out chronic infections such as salmonella  or helicobacter.

The only way to be certain that IBD is or is not occurring in your cat is to do intestinal biopsies. When small snippets of tissue from your cat’s intestinal lining are sent to a pathologist, he/she can see if the typical cells and inflammatory response of IBD are present. Usually, if the problem is not IBD, there will be strong evidence in the examined tissues as to what your cat’s problem actually is. One problem that can be easily confused with IBD is intestinal lymphosarcoma/lymphoma (= lymphocyte cell cancer of the digestive tract). In fact, many veterinarians theorize that lymphosarcomas may, in some cases, be the result of long-standing IBD and it can be very difficult to decide if the lymphocytes present in the lymphocytic / plasmacitic form of IBD are cancerous, pre-cancerous or not.

In late 2015, the Winn Feline Foundation, recognizing how hard IBD and intestinal lymphoma (= lymphosarcoma) are to tell apart, provided a modest grant in the hope of developing a blood test that might help your veterinarian tell the difference. (ref)

The Feline leukemia and Feline Immunodeficiency status of your cat will also be checked. Digestive tract disturbances ,weight loss and intestinal tumors are common when either of these virus are present.

Obtaining intestinal biopsies from your cat can be done in two ways. An incision can be made in your cat’s abdomen and the samples removed surgically. This was once the standard procedure and many veterinarians still do it that way. The advantage is that all areas of the intestinal tract can be sampled and all layers of the intestinal tract can be examined. However it is very traumatic.

A more advanced way is to remove the samples through a fiber-optical apparatus called an endoscope while your cat is anesthetized. However, their are areas of your cat’s digestive tract that are very difficult or impossible to reach with this instrument. If the diagnosis can be made from the samples extracted in this manner, surgery will not be required. If not, it may still be necessary.

The pathologist examining your cat’s biopsy samples will be able to tell which are the predominant white blood cells invading the intestine. If they are lymphocytes and plasma cells, then the cat has lymphocytic/plasmacytic or lymphplasmacytic IBD – the most common type. If the pathologist seems mostly eosinophils, Eosinophilic IBD is the problem. Eosinophilic IBD is probably part of the eosinophilic complex diseases of cats. There are rarer variations of IBD that are occasionally diagnosed (suppurative [resembling pus] IBD, granulomatous IBD, regional IBD etc.).

Intestinal biopsy is an expensive procedure, often requiring a certified veterinary internist working from a veterinary specialty center. Not all pet owners have the money to pay for this service. If you do, have it done. If the biopsies show that your cat does not have IBD, the vet will keep searching for the cause.

If you can not afford endoscopy/biopsy for your cat and IBD is the most likely cause of your pet’s problems, it is entirely plausible to request that your pet be treated with medications and diets that are used to control IBD to see how well they control the problem without endoscopy. This should only be done when the other likely causes of chronic diarrhea have been ruled out. A medication that is often included in an IBD treatment plan is prednisolone . It can be quite helpful in controlling the inflammation caused by IBD. However, occasionally, this drug can also mask other problems, such as intestinal tumors (eg lymphoma). So you may wish to stop short of giving prednisone until you have a clearer diagnosis.

What Treatments Might Help My Cat?

There is no treatment that will cure IBD. But there are many medications and life-style changes that will control it. Some specialists feel impelled to prescribe newer, more expensive and less traditional medications. After all, you took your cat to the specialist for fresh ideas. Some times , these medications are better – but sometimes they are no better than the medications that have been used more routinely for years.

Many of you have access to medications through prescriptions issued for other pets you own or a friend’s pet. Please do not experiment, using them on your kitty because you suspect IBD, without getting the approval of your veterinarian first.

Medications That Work Directly On Your Cat’s Immune System


Corticosteroids (steroids, cortisone, etc.) are very effective in decreasing inflammation. The most commonly used corticosteroid is prednisone. It is very effective in lessening or eliminating the signs of IBD in cats with less of the side effects seen in dogs or people. However, prolonged prednisone use can still have a number of serious side effects. One of them is weight gain and ,perhaps, diabetes. So it must only be used when absolutely necessary and in as small and infrequent amounts as possible. Another problem with giving too much prednisone is that it suppresses the immune system throughout the cat’s body – not just in the intestinal tract. Prednisone, and drugs like it, cause fluid retention, liver changes and a number of other undesirable side effects if they are used too frequently and in too high an amount. Dexamethasone, prednisolone and all common corticosteroids have these same side effects.

A newer corticosteroid which shows promise in IBD is budesonide (eg Entocort® EC). This drug is marketed to treat Crohn’s disease in people. Crohn’s disease is also a form of IBD. Budesonide may cause less of the systemic side effects we associate with corticosteroid use and be less likely to cause diabetes in cats.

In stubborn cases, two other medications that disable the immune system are also used occasionally. They are cyclosporin and azathioprine, two powerful anti-cancer medications. They must be managed carefully with frequent laboratory tests of your cat’s system. They have been known to cause pancreatitis, bone marrow and liver problems. Other similar powerful medications used to disable the immune system after organ transplants or cancer have also been used.


 Sulfasalazine (5-ASA, Salazoprin®, Azulfidine®,etc.) is a sulfa antibiotic. However, it has an anti-inflammatory action inside your pet’s intestine. Because it is poorly absorbed, it does not have the level of side effects that steroids do. So it is often tried in the treatment of IBD before resorting to corticosteroids.

There are a few studies that suggest that omega-3 fatty acids (= ω−3 fatty acids = n−3 fatty acids) are helpful in decreasing intestinal inflammation in people with Crohn’s disease. (ref1, ref2) Since omega-3 fatty acids are not toxic when given in moderate amounts, there is no harm in trying them on your cat. Cold-water fish oil and fish are good sources.

Medications That Slow Down Your Pet’s Intestines and Stop Vomiting

Be very cautious when using over-the-counter human medications in cats. Dogs handle common over-the-counter anti-diarrhea medicines well when the dose give is correct for their weight. But cats may not. Do not give your cat Imodium®  (loperamide) ) or Lomotil® (diphenoxylate) unless a veterinarian you trust is advising you do so. The dose has to be very low and even then, either drugs can cause the cat to become hyper, depressed or have difficulty breathing. When given at too high a dose or for too long, or too frequently they can also cause constipation.

Reglan® (metacloprimide) usually works safely in cats. It can be used intermittently when cats are having vomiting episodes and the cause is known. But Reglan® is not a long-term solution to any disease.

Medications That Protect The Lining Of Your Cat’s Digestive System


When inflammation is severe enough to cause bleeding ulcers of the lining of your pet’s intestine, cimetidine or ranitidine  ,which decrease stomach acidity, or sucralfate which forms a protective barrier against acidity, sometimes help. We know, however, that antacids of the first class also have the potential to let bacteria colonize upper areas of your cat’s intestinal tract where they do not belong – another potential problem. (read here)

Antibiotics That Sometimes Help


An antibiotic called metronidazole (Flagyl®), often helps cats that have IBD. Metronidazole does not only kill harmful bacteria and protozoa that might be compounding your pets problem. Even when harmful bacteria are not the apparent root cause of your pets problem, metronidazole is sometimes effective. We do not know why. Give it several weeks before judging its effect. It will cause some cats to vomit or lose appetite, in which case the dose should be reduced. If the medicine is not in a capsule, expect your cat to drool and hate you.

The biggest barrier to using this medication in cats is its horrible taste. You can get around this by having a compounding pharmacy put the drug into capsules. Not the slightest amount of powder must be on the surface of the capsule. There is a non-bitter form, metronidazole benzoate, but long-term use of benzoate products in cats may not be a good idea. Some compounding pharmacies sell metronidazole in a transdermal gel form. There are mixed feeling as to whether enough drug gets into the cat’s system that way. The only way to know is to give it a try and note the outcome.


Another antibiotic, tylosin (Tylan®), sometimes helps control IBD when it is added to your pet’s food.

I suggest that cats that are not in serious immediate threat from this problem only receive antibiotics when other remedies and diet changes are not enough to keep them under control. That is because antibiotics cause changes in your cat’s intestinal bacteria population that can be difficult to correct even after the antibiotics are no longer required (I discuss that farther down the article under Microbiota transplantation). A 2016 study at the veterinary college in North Carolina shed light on how complex these intestinal interactions really are and showed that negative effects (such as diarrhea) can persist for long after the antibiotics are no longer given. ( read here )

What About Diet Changes And Special Diets For My Cat?

Change in your cat’s diet is the best place to begin when dealing with any long-term digestive problem. In an occasional lucky cat, it is all that need be done. But in most cats, it will be only part of a successful plan to deal with IBD.

Many highly digestible, hypoallergenic and bland diets are commercially available or you can prepared them for your cat at home. You can read some suggestions here. You can also have Balance IT® or an ACVN certified veterinary nutritionist assist you. These diets should be free of preservatives, additives and coloring agents. They should either contain an unusual protein source such as rabbit, venison, cottage cheese or duck or contain proteins that are hydrolyzed into small non-antigenic component molecules (eg Hill’s z/d, Purina HA etc. ). It can take up to several months to see improvement.

Sometimes high fiber diets are helpful. Again, they are available commercially as diabetic and weight reduction formulas (OM, r/d etc) and as fiber supplements. Increased fiber does not help all cats with IBD. Some do better when the fiber content of their diet is actually reduced.

Some cats with IBD have less diarrhea when the fat content (or source) in their diet is reduced. High fiber diets, designed for pet to lose weight are also lower in fat.

Improvement due to diet change in your cat will be gradual. Do not give up too soon.

Can My Cat Be Cured?

Dealing with confirmed IBD in your pet requires a great deal of patience and dedication.

Occasionally, owners see the problem go away with, or without treatment. In these cases, the problems was probably not true IBD in the first place. In true IBD, we can control the problem, but we can not cure it. This is because the underlying biochemical defects that make your cat prone to the problem are not understood. But once you have worked out a special nutrition and life-style plan for your cat, it is a problem you both can live with. There will probably be flare ups when medications will be needed. In some pets, we see the best results when your give medications continuously.

New medications are always being tried. Generally, veterinarians read about them in articles aimed at controlling Crohn’s disease in people and give them a try. Because IBD symptoms in cats have natural peaks and valleys, it can be difficult to quickly decide if any given medication really helps.

Over time, fibrous tissue can build up in the walls of your pet’s intestine and other changes can occur that make it harder for the pet to absorb nutrients and, perhaps, to keep weight on. You can compensate for this with and extra-nutritious diet and supplemental vitamins.

Because there is often an underlying genetic element in this disease, breeding your cat will perpetuate the problem in future kitten generations. So it is not conscientious to do that.

Can Recent Discoveries In Humans With Chronic Intestinal Inflammations Perhaps Help My Cat?

Microbiota transplantation (FMT)


Human physicians are coming to realize that the vast number of micro organisms that naturally live in the large intestine have a tremendous influence on general health. Most cats with IBD or similar conditions have received antibiotics on various occasions. Those antibiotics invariably change the species of bacteria and other beneficial organisms (gut flora) that live in your cat’s intestine. It is possible that those flora changes will not return to what they were prior to antibiotic therapy and that those changes might have a negative impact on your pet’s intestinal health. Your veterinarian may attempt to correct the problem with commercial probiotic pastes. However, those pastes, at best, restore only a small fraction of the species that were lost. Their effect is minimal and short-lived. The best way to attempt to restore your cat’s bacterial flora is through a process called microbiota transplantation (FMT) , in which a complete, healthy bacterial population is transferred by high enema from a healthy pet to your pet. This concept is a new one for most small animal veterinarians. These links will take you to two key articles on the subject (  read here & here ) I will send you the full articles if you ask me to.

IBD is also the most common cause of persistent diarrhea in people. So considerable effort is being made to develop better medications to treat us. Some of those medications might be found to help our pets as well. Eluxadoline (Viberzi®, Truberzi®) is one of them. It was approved by the FDA as an additional option in the treatment of human IBD. (read here) I do not know if it has been tried yet in cats. If you do, please let me know.

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