Dogs and Cats with Diarrhea.. Why Grooming Can be a Cause


What to Expect when you go to the Vet If Your Pet has Diarrhea

(Of Course, your vet may do things a little differently)


If you're old enough to be reading this, I'm sure you know that diarrhea (loose or watery stools) is not a disease in itself, but simply a very obvious symptom that something is not quite right with the intestinal system. We're so used to having a short bout of diarrhea ourselves, that most people don't get too alarmed when they notice their pet has diarrhea, and rightly so; most of the time the problem is minor and self correcting. But sometimes, it's obvious that the problem is more serious, either because the diarrhea has become persistent over the last few days, or the pet is weak and listless, or there are additional problems such as vomiting, or blood in the stool. In cases like this, it's time to have a veterinarian examine the patient.

Here's what to expect:

First, note that it's helpful if you are able and willing to bring in a recent sample of the diarrhea. Also, if you've recently used a household cleaner, fertilizer, pesticide, or rodenticide that your pet may have gotten into, your vet will need to know what the active ingredients are; consider bringing in the container so we can see.

We vets see so many diarrhea cases that we quickly gain the experience that often allows us to narrow down the many possible causes within minutes with just a few questions and a good exam.

On the other hand, other cases of diarrhea take a good deal of detective and laboratory work to figure out.

Diarrhea cases range from very minor to deadly, and from easily cured to terminal. The diseases associated with diarrhea and the resulting dehydration are easily the largest cause of death in humans and other mammals on this planet. So once it's obvious that the diarrhea isn't just a 1 or 2 day affair associated with eating something inappropriate, we take things seriously.

What follows is how we process a typical diarrhea case and some comments to let you know what we're thinking and why we do various tests and so forth.

History and Signalment: Signalment might be a new word for you. It simply means, in veterinary medicine, the basics of what we're talking about: Species, Breed, Sex, Age, and situation. For example: 1 year old, intact male, lab mix dog who roams the neighborhood. That signalment will lead us to suspect problems very different than if the signalment were 8 year old, female spayed, indoor cat.

The history is even more critical than in other diseases in helping us narrow down the likely causes. We need to know if your pet ate anything unusual, was boarded or traveled recently, if there were any big stressful events, and we need an honest report of the pet's diet. We also need an accurate vaccination history since so many of our diarrhea deaths are associated with pets that weren't protected with a high quality vaccine program.

A Good Examination:

Your vet will go over your pet from head to toe, getting an assessment of general health, hydration status, circulation problems, GI pain and distress, as well as pick up any secondary problems that might be important.

Frequently, with just the history and exam, your vet may be able to guess correctly that the problem is not too serious and send you home with inexpensive medicines that are likely to solve your pet's problem and discomfort in short order.

But if, because of the history, signalment, or exam, little alarm bells are going off, your vet will recommend a few tests, possible hospitalization, and in some cases aggressive treatment such as IV Fluids etc. I'll describe the different tests your vet may recommend in just a minute, but first, let me give you a list that summarizes the different categories of diarrhea based on's how most of us vets were taught to narrow down a medical case:

Possible Causes of Diarrhea in General Terms:

1. Viral: Our most common cause of deadly diarrhea in puppies, with parvo and distemper virus' being the biggest culprits. I can't emphasize too much how important it is to have your young puppies vaccinated with high quality vaccines. While viral diarrhea is most common in poorly vaccinated puppies, it's also an occasional problem in kittens, cats, and dogs too. Also keep in mind that vaccination programs only protect your pet from the most common viral diseases and the most common strains of the virus; vaccines greatly reduce the chance of succumbing to viral diseases...but not by 100% by any means. And not all brands of vaccines are created equal. It's important to use the newer and better vaccines. Your vet will be using these. Your mail order company may not. For more about vaccine quality go to our page on vaccine recommendations. Just for the record, Feline leukemia, Aids, and Infectious Peritonitis are cat viral diseases that are sometimes associated with diarrhea. The lab tests and treatment options we have for the different types of diarrhea are discussed a little further on.

2. Bacterial: Pets frequently take in large amounts of bacteria into their mouth, what with licking everything, eating rancid garbage or "road kill", drinking out of puddles, and grooming with their tongue. But if your pet is in otherwise good health, free of parasites, on a good diet, and hasn't recently undergone an event stressful to the immune system such as pregnancy or surgery, it's unlikely that much of this bacteria will be able to get past the acidic stomach, the immune system defenses, or the competitive "good" bacteria of the gut in numbers large enough to cause much trouble for long.

You've probably have heard of the bacterias' e-coli, clostridium, and salmonella and the occasional high profile deaths they cause when people get food poisoning at restaurants, church picnics, and the like. Well, every once in a while, pets also get food poisoning that becomes more serious than usual. In addition to food sources, pets can get bacterial infections of the bowels from infected gums, from any diseases or problems that inflame the bowels, and possibly due to long term or inappropriate antibiotic therapy.

Bacterial infections of the gut are sometimes a problem in addition to some other primary problem. For example, bacterial infections are a common problem in dogs whose intestinal tracts are all irritated from parasites or viruses. As always, your vet won't assume your pet has a single problem. Like most things in life; "Trouble Likes Company".

3. Parasites: Worldwide, diarrhea due to parasites is a major problem. But in those countries where people love and care for their pets, and can afford to take advantage of veterinary services, severe problems aren't as common anymore. But even with all our new and approved parasite control products, and even if your pet has been taking them, we occasionally get an outbreak of diarrhea due to intestinal worms, protozoa, amoebas, and other parasites. Like bacteria, microscopic parasites are all around us in our environment waiting to take advantage of any pet whose immune system is weakened.

And the little buggers keep mutating and getting resistant!

As an aside; we highly recommend that you follow your vet's recommendations for a parasite control program. Our newest products are safe, flavored, more effective than ever before, and much less expensive than the cost of treating the diseases they prevent.

Another aside; you don't think we do so many fecal sample tests because we like it do you? Parasites continue to be a big problem despite what I just said praising our newer parasite control products.

4. Garbagitis: This non-medical term is a used to describe all the possible, inappropriate things that pets sometimes eat, including garbage. Table scraps that were too rich or spicy, dead animals, sticks, leaves, dirt, underwear, socks, toys, balls, and frequently; plastic wrap. If your vet suspects that your pet is suffering from GI (gastro-intestinal) irritation due to something like the items mentioned above, he or she may very well give a mineral oil based laxative in hopes of evacuating the bowel. This sometimes confuses people since laxatives make diarrhea worse, temporarily, and are usually used for constipation, not diarrhea. Another case of "Doctor Knows Best". Also note, if a foreign body is suspected, your vet will probably recommend radiographs and/or ultra-sound.

5. Metabolic or Organ Disease: The various systems in the body are very much inter-related, and diarrhea is often the most obvious symptom of other diseases such as liver disease, pancreatitis, kidney disease, and hormone imbalances. We become especially suspicious of such diseases in middle age and older pets. In many situations, your vet will recommend blood work to rule out such diseases.

6. Diet Related: A large number of diarrhea cases are solved by switching to special diets that are easy to digest. Or are non-allergenic to your pet.

Or more consistent or of higher quality. Once your vet rules out other causes of frequent or chronic diarrhea, he or she may very well recommend a feeding trial of a special diet. It's important to understand, here, that just switching from one brand to the next is unlikely to work...most brands of pet foods contain similar ingredients, any one of which might be causing the problem in your pet.

7. Hair: I've listed hair all by itself since it's so often the problem in both diarrhea and constipation...especially in cats. Many cats and dogs shed excessively and therefore lick and swallow too much hair to digest easily which means the hair ferments in the lower bowel (instead of being digested in the upper bowel) (cheap pet food ingredients cause a similar problem). This fermentation process in the lower bowel (similar to humans eating beans) causes irritation to the colon which in turn causes diarrhea.

Anyhow, sometimes the real solution involves reducing the shedding by treating the underlying skin problems, whether it be allergies, poor diet, parasites, inadequate grooming, or deficiencies in fatty acids.

And you may find it intersting that every once in a while cats and dogs groom excessively due to people who chew their nails. Maybe a case for Prozac!

8. I'm running out of steam. So number 8 is everything else:

Such as Cancer, Lymphoma, the secondary affects of chronic diseases, Chronic Bowel Disease, Stress and Anxiety, Fungal, Pancreatic Insufficiency, side effects of certain medications, and probably a few things I've forgotten.

Okay, back on track...What to expect at the vet:

Once the history is established and an initial exam is completed, your vet may have good reason to recommend some tests. Here's a short description:

Lab Tests and Imaging Techniques Your Vet May Recommend:

I'll make some appropriate comments about each of the following soon...

- Fecal test for blood, mucus, and parasites

- CBC & Chemistry

- Thyroid Testing

- HelioBacter Test

- Culture and Sensitivity

- Radiographs

- Ultra-sound

Possible Treatments for Less Severe Cases:

NPO: Nothing by mouth or fasting for 12-24 hours. This allow the GI tract to "settle down" Witholding of food and water is a more common treatment for vomiting than diarrhea, actually, but sometimes it helps with diarrhea too. I usually opt for feeding small amounts of easily digested food (chicken and rice) given in small amounts at a time.

Anti-diarrheals such as kaopectate, pepto-bismol, or amodium-D: These over the counter products are appropriate for treating at home for minor cases of diarrhea when your pet seems otherwise bright and alert and normal. If they aren't working after 1-2 days, then you should assume you're missing something and ought to make an appointment with your vet.

These medicines are much more likely to work if you use 2-3 times more than the approved dose, but that brings up a legal problem in the rare event that your pet overdoses.

An aside; This business of using medicines or doses that aren't officially approved by the FDA for a particular species is a common problem for veterinarians. There are a lot of medicines that we have learned from experience and from our mentors over the years that are usually safe and effective, but have never gone through the expensive process of being approved by the FDA for pets. Kaopectate and Pepto are good examples of old medicines that we know work better if you give more than the label directions, and that such doses are safe UNLESS the patient is dehydrated sickly, weak, obstructed, or sensitive. In other words, we need to examine the pet before we can legally or professionally feel comfortable about giving specific medical advice over the phone..even for simple medications like kao-pectate!

Donnagel or Bella Donna Alkaloids: Usually more effective than over the counter medicines. Your vet will prescribe them if needed. In addition, there are quite a few other anti-diarrheal meds your vet may recommend, including herbals, homeopathic, and familiar products like kaopectate etc.

Lomotil, Loperimide, or opium derivatives: more expensive, usually more effective, and usually reserved for more troublesome cases of diarrhea. Definitely given under the supervision of your vet.

Actually treating the problem if a specific diagnosis is made such as treating for any parasites found, liver disease, kidney disease etc. Always remember that diarrhea is often just a symptom of some hard to detect disorder, disease, or organ failure

Diet changes are often the solution, especially for pets with fairly frequent diarrhea problems

Metronidazole is a broad spectrum, inexpensive, and safe antimicrobial used to treat the amoebic parasite Giardia . Maybe more important, this medicine seems to help correct any imbalance in the normal gut flora. Flare ups of "over-riding" bacteria, protozoa, and amoebas are often associated with diarrhea either as the cause or as a result, so your vet may want to prescribe this medication to your pet.

Supportive Care: Perhaps the most common treatment and most important in serious cases of diarrhea is what we call supportive care. This means keeping the patient well hydrated, well nourished, warm and comfortable, as well as minimizing symptoms such as fever, nausea, chills, and the diarrhea itself. IV Fluids are the backbone of supportive care in serious cases.

Antibiotics: Antibiotics are often used in severe diarrhea cases even when we don't suspect bacteria as being the cause of the diarrhea! Why? For several possible reasons: To prevent bacterial infections of the gut at a time when we suspect the GI tract to be inflammed and vunerable. To prevent respiratory, liver, and other organ system infections at a time when we suspect the immune system to be weakened. And to prevent bacterimia. Bacterimia is a big deal and refers to bacterial infection of the blood. It can occur with diarrhea because if the gut wall is inflammed and damaged, then the bacteria that is inside the gut can get across the gut wall into the blood stream. Once inside the blood, the bacteria will float around the body looking for a place to thrive, which of course, can cause a lot of problems: liver disease, joint disease, heart valve disease, pneumonia, and on and on.

I hope the above has been helpful. As with all my pages, I'll try to review, edit, and improve this new page soon. Feel free, especially if you're a veterinarian, to make comments, additions etc by eMail: [email protected]

However, I've stopped trying to respond to the many eMails I get asking me things like how do I treat such and such (ie my goat with diarrhea) or asking for second opinions about what their vet did etc. For legal reasons and because it takes a lot of time...not to mention a careful exam...I can't offer specific medical advice over the phone or the internet other than the very helpful, but general, information I've already have given you on this site.

What follows are some additional articles that should be helpful. Provided as a courtesty by the people at Hill's Prescription Diets


Colitis is an inflammation of the large bowel (colon). This inflammation may be acute (sudden onset of brief duration) or chronic (long-term), disrupting your pet's normal bowel habits.

Acute colitis occurs most commonly in dogs and frequently responds to one to three weeks of therapy. Chronic colitis can go on for several years or perhaps a lifetime.

Signs of Colitis

Some dogs and cats may have minor clinical signs; others have severe and sometimes disabling or fatal signs. Dietary therapy and certain medications can help control the inflammation and most signs, but they generally do not provide a cure.

The inflammation in chronic colitis leads to excess water in your pet's stool. This is manifested as diarrhea; you most likely will see the frequent passage of small quantities of mucus and/or blood-streaked stools. The diarrhea may be intermittent or continuous.

Abdominal pain, depression, fever, weight loss, and a dull coat may also be present.

Causes of Colitis

Many things can cause colitis, as can be seen from the following list. In many cases, the exact cause of colitis may never be determined.



2.Spastic colitis

3.Bacterial colitis

4.Fungal colitis




2.Eosinophilic colitis

3.Ulcerative colitis





8.Allergies (including food allergies)

9.Foreign body

10.Spastic colitis

11.Histocytic ulcerative colitis

12.Plasmacytic lymphocytic colitis

13.Immunoproliferation enteritis

Diagnosis of Colitis

If your veterinarian suspects that you pet has colitis he or she may perform some, most, or all of these diagnostic tests: abdominal palpation, rectal exam, white and red blood cell counts, blood chemistry profile, urinalysis, multiple fecal examinations, bacteriologic cultures of feces, x-rays of the digestive tract (possibly with barium), colonoscopy (examination of the colon through a small, lighted tube inserted though the anus), biopsy of the colon, and exploratory surgery of the abdomen.

To evaluate how your pet is responding to therapy, your veterinarian will periodically repeat some of these lab tests.

Management of Chronic Colitis

Remember, few cases of colitis can be cured. The goal of therapy for chronic colitis, therefore, is to enable your pet to maintain as normal a lifestyle as possible. Diet and drugs can generally suppress the inflammation in your pet's colon and help prevent recurrences.


Many cases of chronic colitis respond to one of two dietary approaches: 1) Increasing the amount of fiber in the animal's diet or 2) Feeding a diet that is not likely to stimulate an allergic reaction (hypoallergenic diet). There is no way to predict which approach might be better for your pet.

Based on experience treating colitis, your veterinarian will recommend one approach or the other. Follow the directions explicitly - feed no other foods or treats. If your pet is taking any other medicine, tell your veterinarian about it so that interactions between the diet and medicine can be controlled.

A trial with a therapeutic diet usually takes three to six weeks before your veterinarian will be able to accurately assess the results of the trial. Be patient, and remember, diarrheas in some pets may actually worsen for a few days while the pet's digestive tract is becoming accustomed to the new diet.

Your veterinarian will recommend the best diet for you to follow for your pet...... follow it!

Importance of Fiber

Fiber is a carbohydrate in our diet that cannot be digested by enzymes. There are two kinds of fiber: one is soluble in water; the other is not. Insoluble fibers provide bulk to the diet and help food and water move through the digestive tract.

It is well established that fiber-rich diets can be used to manage constipation in pets because fiber increases water retention in the intestines which softens the stool. The increased bulk also increases the propulsive movements of the intestine, helping to alleviate the constipation.

Amazingly enough, fiber also can be used to treat some diarrheas. In diarrheic animals fiber normalizes intestinal transit time, which increases water absorption form the colon. Therefore, there is less water lost in the stool. That's why high-fiber diets have a place in the treatment of colitis.


Many drugs used to control chronic colitis have side effects and may even be dangerous - your veterinarian will prescribe them with caution. Drug therapy involves five categories of medications:

1.Drugs that relieve diarrhea

2.5-aminosalicylic acid

3.Steroids for relief of inflammation

4.Drugs that suppress the immune system


Constipation and Diarrhea

Signs of Constipation

A constipated dog or cat exhibits infrequent or difficult evacuation of the feces or stool. The feces is usually hard and dry which increases straining and reduces stool volume.

Causes of Constipation

Many things may cause constipation, but the most common are dietary and environmental factors.


Fiber in the diet is important for normal defecation in dogs and cats, just as it is for humans. Insufficient dietary fiber can cause constipation.

Substances such as hair, bones or foreign materials ingested by a cat or dog can form hard masses or concretions when mixed with feces and cannot be eliminated, resulting in constipation.

Water is essential to proper gastrointestinal function; therefore, if an animal is deprived of water, it will become constipated.

Environmental factors:

Changes which affect an animal's daily routine such as a hospital stay or lack of exercise can also result in constipation.

There may be many other causes of constipation such as those listed below:


·Fractures of the pelvis or pelvic limbs

·Lesions around the rectum

·Prostate Disease

·Spinal Cord or Disc Disease

·Large Bowel Nervous Disorders


·Metabolic or Endocrine Disorders



Treatment of Constipation

To treat your pet for constipation, the underlying cause must first be determined.

Your veterinarian will perform a physical examination of your pet and will ask you about your pet's medical history, its diet and its daily routine. Blood tests, x-rays or other tests may also be necessary and will be explained to you prior to testing.

If it is determined that the underlying cause is due to disease or trauma, medical treatment may be necessary to correct the problem.

Home Care Management for Constipation

Diets rich in fiber can be used to aid in the management of constipation in pets as in humans. The fiber increases water retention in the intestines which softens the stool. The increased bulk also increases the propulsive movements of the intestine, helping to alleviate the constipation.

1.Twice daily, feed your pet a diet containing at least 10 percent fiber to stimulate bowel movement (your veterinarian will advise you on a specific diet).

2.Do not give your pet bones or snacks and restrict access to foreign materials. Long-haired animals should be brushed daily. This will help remove excess hair that the animal might otherwise ingest.

3.Thirty to 60 minutes after eating, exercise the dog to encourage defecation.

4.Provide free access to fresh water.

Managing your pet's care at home is an important part of its treatment. It is essential you follow your veterinarian's instructions. If you have any questions about your pet's medical care, please do not hesitate to ask. Your questions are welcomed by the hospital staff.

Signs of Diarrhea

Diarrhea in a dog or cat is characterized by abnormally frequent, watery stools. Clinical signs associated with diarrhea include frequency of evacuation of loose feces which results in an increase in the volume of feces passed. The diarrheal feces contains not only increased amounts of water and electrolytes, but may also contain mucus, blood, fat or undigested food.

Diarrhea can originate from the small intestine or the large intestine (colitis) and is further subclassified as acute (sudden onset of brief duration) or chronic (long-term). (See Colitis for a discussion of that condition.)

Acute Diarrhea - Small Intestine

Acute diarrhea originating in the small intestine usually lasts less that 48 hours. The feces seldom contains mucus, but it is not uncommon to find blood in the feces. The animal usually loses its appetite or is anorexic. The feces is brown or reddish-brown in color. The animal exhibits a sense of urgency to defecate as well as an increased frequency and may continue straining after defecation.

Chronic Diarrhea - Small Intestine

Chronic diarrhea originating in the small intestine lasts 7-10 days or longer. The animal passes a large volume of watery feces and has bowel movements two or three times as often as its normal frequency. The feces is brown in color unless there is blood in the stool in which case it will have a black, tarry appearance. Little or no mucus is present in the feces (as opposed to Colitis which may have much mucus in the diarrhea).

Causes of Diarrhea

The causes of diarrhea vary widely, but include bacteria, viruses, internal parasites and stress-induced factors. Diarrhea may also be caused by toxic substances which the animal ingests or by food allergies. A change in pet food, eating table scraps or rich snacks, or scavenging spoiled food from garbage may result in diarrhea as well. Organ dysfunction, especially the liver and pancreas, can cause diarrhea.

Diarrhea caused by internal parasites may be a continuous, chronic problem or be intermittent with a normal stool being passed between abnormal stools. Some parasites causing diarrhea in dogs and cats are transferable to humans. Therefore, it is important to identify the parasitic causes.

It is important to note that young animals may be more severely affected by diarrhea than mature animals. Puppies should be carefully observed because their condition could quickly become life-threatening.

However, it is important to differentiate between non-specific diarrhea and diarrhea caused by a more serious health problem.

To treat your pet for diarrhea, your veterinarian must first diagnose the underlying cause.

Treatment of Diarrhea

Initially, your veterinarian will perform a physical examination of your pet and will ask you question about its health history and its diet and daily routine. Often the diagnosis can be made from the health history and physical exam and a treatment can be prescribed.

It may be necessary to withhold all food from your pet for one or two days. The more severe the intestinal disturbance, the longer the period the food must be withheld.

Continue to give your pet water during the fasting period.

If your pet is severely dehydrated, intravenous (IV) fluids may be necessary before any diagnostic studies are begun.

Your veterinarian may ask you to collect a fecal sample for microscopic examination to help diagnose the cause of the diarrhea. You will be given a plastic bag or container and instructed on how to obtain a fresh stool sample. Numerous fecal exams or rechecks may be necessary to detect internal parasites which can show up intermittently in the feces.

In some cases of chronic diarrhea, a biopsy is necessary. This procedure involves obtaining a very small section of tissue from the intestine for microscopic study. This can be done through a small incision in the abdomen and involves only a few stitches to close.

Home Care Management for Diarrhea

1.After your pet has fasted the prescribed number of days as determined by your veterinarian, gradually return it to full feed

2.Feed small amounts frequently (3 to 6 times daily)

3.Feed a highly digestible diet containing one percent or less fiber in the dry matter. (This is very different than the recommendation for Colitis in which a diet high in fiber is often indicated.)

The diet for small intestinal diarrhea should provide a moderate amount of highly-digestible protein from cottage cheese, chicken and egg, and not more than 15 percent fat. Carbohydrates should be easily digestible such as those from rice or dextrose.

Avoid diets with the following ingredients: wheat middlings, bran, and other cereal by-products; lactose (milk sugar) and foods containing more than 10 percent sucrose (table sugar). Do not give your pet bones, snacks or table scraps which may irritate the intestinal tract.

Watch your pet at home - checking for recurrent bouts of diarrhea, blood or mucus in the feces, foreign material in the feces, and frequency of defecation. If any of these signs recur or if your pet becomes weak or loses its appetite, please call your veterinarian.

Managing your pet's care at home is an important part of its treatment. It is essential that you follow your veterinarian's instructions. If you have any uestions about your pet's medical care, please do not hesitate to ask your veterinary staff.

Salmonellosis (One of the main causes of Food Poisoning)

Salmonellosis is an intestinal tract disease that comes from exposure to large amounts of the bacteria ...usually on contaminated food. Since salmonella is passed in affected animals, humans, and fowl through the feces, what's going on here is a combination of fecal contamination of the food along with enough time (the warmer the faster) for the bacteria colony to multiply. This is why we are so careful to keep meats refrigerated, why we hope that restaurant workers wash their hands frequently, and why we don't share cutting boards and utensils between precooked food and cooked food. Pets that eat garbage or road kill are very likely to be exposed. Whether or not they become clinically infected and diseased will depend on their natural immunity, general health, and probably luck.

Signs of salmonellosis include vomiting, diarrhea with or without blood, fever, and dehydration. Severe infection with Salmonella can be fatal. The disease is most common in young, stressed, weak, or old animals. Some animals can carry and spread the disease without having signs of illness themselves.

Salmonellosis is a public health concern, because these bacteria can also infect people. Strict hygiene should be practiced when infected animals are handled. This includes carefully disposing of fecal material, cleaning litter boxes and utensils, and frequently washing hands. Children should not handle infected pets.

In order to diagnose salmonellosis for certain, we need to culture the feces. Since we need to start treatment before waiting for the results (cultures take at least 4 days to grow out), we often skip this step. Depends on the situation.


Infected animals are generally hospitaized and given IV Fluids, antibiotics, anti-diarrheals, and supportive care till better.

Article submitted by: © Roger Ross DVM