Colitis and Bowel Disease in Dogs and Cats

Colitis and Bowel Disease in Dogs and Cats

Stomach upset is a frequent problem we face, and it is common in our companion dogs and cats as well. Occasional bouts of diarrhea are generally not a cause for concern and can usually be treated symptomatically. Chronic diarrhea usually signifies an underlying medical problem that must be addressed.

In this article, we are going to learn about colitis, chronic inflammation of the large intestine or colon, its causes, treatments, and preventions.

The Digestive Tract

Before we can begin to learn about digestive disorders, we must have an understanding of the digestive tract and how food is broken down and nutrients absorbed.

Mouth and Stomach

The digestive process begins in the mouth as food is broken down into smaller pieces by chewing and is mixed with a digestive enzyme called amylase, which breaks down carbohydrates into simple sugar. (Cats do not have amylase in their saliva, so cannot digest carbohydrates well.) Saliva mixes with food in the mouth, which lubricates it for its journey through the esophagus to the stomach.

In the stomach, the slurry of food and saliva is made acidic by secretions from the stomach lining, mixed with more digestive enzymes, and ground-up further by contractions of the stomach.

Small Intestine

Once the stomach is finished grinding up the digestive mix, it sends the food to the small intestine. The small intestine has three parts; the duodenum, jejunum, and ileum. Food moves through the sections of the small intestine in that order. In the duodenum, more digestive enzymes produced by the pancreas and the liver are added. Once food leaves the duodenum the digestive processing (breakdown) of the food is complete, and the process of absorption of the nutrients begins.

The majority of the nutrients in the digested food are absorbed as the mixture travels through the jejunum and ileum.

Large Intestine

The large intestine is also called the large bowel, or colon. The digested mix that leaves the ileum and enters the large intestine is primarily composed of a material that cannot be broken down (or digested) any further. The main functions of the large intestine are to absorb water and the remaining nutrients from the digestive mix, and store stool.

Bacteria and Digestion

The small and large intestine are filled with bacteria that aid the digestion of food and absorption of nutrients. The large intestine has about 10 times as many bacteria as the small intestine. Without these good bacteria in the intestines, our bodies cannot get all the nutrients they need from food. Antibiotics, while sometimes needed for certain infections, must be used with caution because they not only kill harmful bacteria but the needed, helpful ones, too.


Colitis means inflammation of the colon. The word is usually associated with diarrhea, and in fact, diarrhea is a common symptom of colitis. Colitis is sometimes referred to as Inflammatory Bowel Disease (IBD), Spastic Bowel Syndrome (SBS), Irritable Bowel Syndrome (IBS), or Lymphocytic-plasmacytic Inflammatory Bowel Disease (LIBD). The substitution of terms is not entirely appropriate. All of the diseases mentioned lead to colitis (inflammation of the colon) and associated symptoms, including diarrhea. However, to appropriately treat colitis, it is vitally important to know the cause.

Symptoms of Colitis

The primary symptom of colitis is diarrhea or loose stools. When diarrhea happens as a single episode, the term used is Acute Colitis. When it occurs frequently (as often as daily) we use the term Chronic Colitis. Other symptoms of colitis include:

  • Blood or mucus in the stool
  • Painful or difficult bowel movements
  • Excessive straining with bowel movements
  • Decreased energy and/or loss of appetite
  • Tender and/or distended abdomen
  • Vomiting (usually only with problems of the small intestine or stomach)

Common Causes of Colitis

Identifying the cause of colitis is extremely important because treatment for one cause can frequently make colitis caused by a different disease process worse.

Acute Colitis generally arises from episodes of raiding the garbage and eating inappropriate things or consuming a meal of unfamiliar food.

Chronic Colitis is usually the result of poor diet or food allergies or an underlying medical condition. Many apparently unrelated conditions, such as immune system disorders, can manifest as colitis. Below are the most common causes of chronic colitis.


Parasites that cause colitis include Whipworms, Giardia, Trichomona, Amoeba, and Balantida. Bacterial infections that cause colitis are Salmonella and Campylobacter. Though there is some overlap, parasitic infections usually arise from drinking contaminated water, and bacterial infections result from ingesting contaminated food.

Foreign Body

Eating indigestible material like straw or dirt can irritate the colon, which leads to inflammation. Some animals develop the tendency to eat foreign materials regularly, and this can lead to chronic colitis.

Inflammatory Bowel Disease

IBD is a serious disease that is frequently difficult to treat. It is characterized by an invasion of the colon walls by the body’s own inflammatory cells (cells that normally fight infections). This leads to a persistent state of inflammation of the colon lining and a complete disruption of its normal functioning.

Irritable Bowel Syndrome

In IBS there is no inflammation of the colon, but instead hyperactivity. Essentially, the colon constricts much more than it should and the waste products are moved through at a rate too fast for the absorption of the water and nutrients. IBS is usually associated with neurological or psychological problems; for example, a dog or cat that is stressed, overworked, or anxious.

Other Causes

Syphilis is an inflammation of a small, dead-end pocket where the small and large intestine connect. Cancer can also lead to colitis with associated diarrhea or loose stools. The most common forms are lymphosarcoma, a cancer of blood cells, and adenocarcinoma, cancer originating in the glandular cells lining the colon. Over vaccination has also been linked to chronic digestive problems by some experts.

Making the Diagnosis

Environment, lifestyle, and diet have all been shown to be related to the causes of Colitis. A holistic veterinarian is trained to take all of these into account when looking for the cause in your animal. Ascertaining the cause of colitis requires a complete history, physical exam, and usually laboratory tests.


A thorough history will be the first step taken by your holistic veterinarian and is very important in making the diagnosis. For example, IBS is likely in a dog or cat who is suddenly left alone for long periods of time. Alternatively, an allergic reaction is probable if your companion was recently begun on a new diet, treat, or supplement.

Physical Exam

Your holistic veterinarian will also perform a physical exam, however, the exam will likely be normal with the exception of abdominal tenderness or mild distention.

Laboratory Tests

Your cat or dog’s stool may be tested for the presence of parasites, bacteria, blood, and undigested nutrients. The presence or absence of any of these can lead to the diagnosis of the exact cause of the colitis. Blood may be tested for blood cancers, or for indications of hypersensitivity to certain food products or additives.

Other Testing

Muscle Testing or Kinesiology may also be used to compare the strength and weakness of any muscle (also known as neuromuscular sensitivity testing (NST) of the body in the presence and absence of any substance. A measured weakness in the presence of a substance is due to the effect of an allergy to the item with which the animal has contact. This is a simple and completely non-invasive method used to detect allergens.

In severe cases, or those that don’t respond to any treatment, x-ray tests, or a colonoscopy (a visualization of the colon with an extended, flexible microscope) may be needed.

Treating Colitis

In most cases, a single episode of diarrhea is self-limiting and will resolve on its own. Your holistic veterinarian should evaluate diarrhea lasting longer than 24 to 48 hours, or if there is associated fever or abdominal distention.

Many conventional and alternative treatments are available for the disorders associated with chronic colitis. The treatment used will depend on the underlying disease.

Conventional Treatments

Conventional treatments for colitis include antibiotics for infections, anti-inflammatory drugs, or even chemotherapeutic agents for the severe types of inflammation found in IBD. IBS is often treated with behavior modification or drugs that reduce anxiety. Most conventional treatments have their own, sometimes serious, side effects.

Alternative Treatments

Many safe and effective alternative treatments are available to treat the causes of colitis.

A host of herbal therapies are useful for treating colitis. Wormwood is used for expelling tapeworms, and garlic is considered an effective dewormer and preventative. A combination of 2 parts slippery elm and one part each of marshmallow root, licorice, and fennel seed is effective in treating IBD. Peppermint is useful in the treatment of IBS. Animals Apawthecary Pytomucil Herbal Tincture is useful for treating many of the causes of colitis and does not have the side effects found with conventional drugs. To explore herbal treatments further, the definitive resource for using herbs to treat our companion animals is, All You Ever Wanted to Know About Herbs for Pets, by Mary Wulff Tilford and Gregory Tilford.

Acupuncture has been used successfully to treat causes of chronic colitis including IBD and IBS. Additionally, combination Homeopathic Remedies are available to treat acute and chronic colitis. Other useful treatments include Flower Essences and colloidal silver.


We have all heard the saying that pets and their owners grow to look alike. This applies to their temperaments as well. A stressful environment affects us as well as our companions. If we feel stressed and out of balance, so do our companions. Reducing stress and creating a predictable, calming and supportive environment has been found to reduce the symptoms of colitis in humans and animals.

The Importance of Diet and Nutrition

A poor quality diet and allergies to additives in commercial feeds are leading causes of chronic colitis in cats and dogs. The importance of a high-quality diet and proper nutrition, including supplements, cannot be overstated. In many cases, changing your companion’s diet to one that is protein-based and contains only natural preservatives, along with the addition of supplements, can resolve chronic colitis. Many owners find that colitis responds to simply changing to a raw or home-cooked diet. Changes in diet should be made gradually, and it can take up to 8 weeks to see a response.

As cats and dogs age, the numbers of beneficial bacteria in both the small and large intestine decrease, as do the amounts of digestive enzymes produced by the stomach, liver, and pancreas. A decrease of these necessary bacteria and enzymes can lead to changes in the digestive mix that reaches the colon and subsequent inflammation. Animal Essentials Plant Enzymes and Probiotics restore the loss of enzymes and probiotics that results in aging. Ark Naturals Gentle Digest is wonderfully beneficial, as it provides healthy intestinal bacteria and encourages their growth. AddLife by Wysong is another excellent supplement that aids in all aspects of digestive function.


Many dietary supplements in addition to probiotics and digestive enzymes are useful in treating chronic colitis. Some are L-Glutamine, N-Acetyl-Glucosamine, and L-Glycine. Solid Gold Life Extension is a combination of supplements that is formulated specifically for senior cats and dogs with the immune system and digestive disorders.

Dietary Fiber

A great deal of information is available regarding the effect of dietary fiber on colitis, and it is generally felt that an increase in fiber improves digestion and reduces the symptoms of chronic colitis. Fiber is classified as soluble and insoluble, and it is best to ask your holistic veterinarian which may be most appropriate for your companion

Fructooligosaccharides (FOS)

FOS are carbohydrates made by combining two naturally occurring sugars, fructose, and glucose, and are included in some prescription diets used to treat colitis. FOS are digested by the large intestine and felt to inhibit the growth of harmful bacteria and support the growth of healthy bacteria.


As the leading causes of colitis are poor diet and nutrition, food allergies, including reactions to preservatives in commercial feeds, and stress, one reason accurately that prevention includes high-quality food and nutrition, and a predictable lifestyle that includes daily exercise. Higher levels of dietary fiber than present in most commercial feeds may also have a protective effect against the occurrence of colitis.

Long-Term Commitment

Chronic colitis is a recurring condition with many diverse causes. The commitment you make to your companion seeking out the cause of their condition and the most appropriate treatment, including the proper diet and supplements, will be rewarded with many years of their faithful and loving presence.

You can also check our article about chronic renal failure in senior cats and dogs.



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