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Dog Diarrhea

Dog Potty Training

Diarrhea is defined as an abnormal increase in the amount of fluid in the feces. It is often accompanied by an increase in the volume and frequency of stool passage as well. As a dog-lover, you probably know what this means. A sick dog, a stinky mess, countless trips outside, extensive household cleanup, and a miserable experience for canine and human alike. The bad news: nearly all dogs get diarrhea sooner or later. This stems in part from—let's face it—a dog's disgusting eating habits. Table treats, garbage, rocks and mulch, rotting carrion, feces, other unmentionables, or just plain overindulgence in general, can give Rover the runs. The good news: most cases are mild and self-limiting. Some knowledge of the causes and treatment of diarrhea can help you be better prepared when diarrhea strikes.

Dietary lapses are just one of dozens of potential sources of doggy diarrhea along with viral infections, parasites, food allergies or intolerances, bacterial infections, and inflammatory disorders (scroll down for partial list). Veterinarians can begin honing in on the cause of your dog's diarrhea by classifying it based on its duration, location, and severity. By learning the classification system, you, too, can do some detective work.

Causes of Dietary Diarrhea in Dogs

Some of the common causes of diarrhea in dogs that is related to diet include:

  • Overeating
  • Ingestion of garbage, carrion, or spoiled food
  • Ingestion of plants, sticks, rocks, bones, fabric, carpet, or other indigestible materials
  • Coprophagia (eating poop)
  • Abrupt diet changes
  • Poor quality diet
  • Dietary intolerance, e.g. to fatty foods, spicy foods or food additives
  • Lactose intolerance
  • Food allergy, e.g. to milk, wheat gluten, soy, corn, beef

Acute vs. Chronic Diarrhea in Dogs

Acute diarrhea in dogs is common. It has a fairly sudden onset and lasts a week or less. The most common causes of acute diarrhea include dietary issues (see box), viral infections, and intestinal parasites. An abrupt diet change can give a dog the runs as can dairy products, since many dogs are lactose intolerant. A stressful event can also trigger diarrhea.

Diarrhea is considered chronic if it persists for three weeks or longer despite treatment or recurs repeatedly over time. Chronic diarrhea can be associated with certain parasites, food allergies, inflammatory bowel disease, pancreatic disorders, and systemic conditions such as liver problems, lead poisoning, and cancer.

Small vs. Large Intestinal Diarrhea in Dogs

The type of signs your dog is having can pinpoint the problem area. Diarrhea that originates from the small (upper) intestine may be soft to liquid, foul-smelling, fairly voluminous, and variable in color. There is often flatulence. Your dog may or may not ask to go out more often, but accidents and urgent trips to the bathroom are rare. Small intestinal diarrhea would not be expected to contain visible blood. Food intolerance, pancreatic insufficiency, and inflammatory bowel disease are common afflictions of the upper small intestine.

Diarrhea that originates from the large (lower) intestine is a different matter. Dogs with colitis (large intestinal diarrhea) are plagued by frequent and sudden urges to defecate. The dog will repeatedly ask to go out, even during the night. Lapses in housetraining are common. Each bout of colitis yields small amounts of lumpy or liquid feces that may contain drops or streaks of blood and mucus. Dogs may position and reposition as if to defecate, each time only squeezing out a few drops. This so-called "colitis dance" is a classic sign of lower intestinal diarrhea, but it can be misinterpreted by dog-owners as constipation. Common causes of colitis include whipworms, giardia, fiber-responsive diarrhea, and stress colitis.

Mild vs. Complicated Diarrhea in Dogs

Many cases of canine diarrhea are mild and self-limiting. They respond well to simple treatment and home care. At other times, diarrhea can be part of a more complex medical picture. Fluid loss from diarrhea of any cause, especially when accompanied by vomiting, can rapidly lead to dehydration and serious health consequences. This is especially true in puppies and older dogs. Chronic disorders of the small intestine typically cause weight loss and malnutrition as time wears on. Some forms of acute diarrhea can be life-threatening and require aggressive intervention. These include distemper, parvovirus infection, intoxications, and intestinal obstruction.

Causes of Doggy Diarrhea

(Partial List)

Diet change

  • Food Intolerance or Allergy
    (e.g. wheat gluten, fatty foods, dairy products)
  • Garbage Ingestion
  • Foreign Material
  • Toxins (e.g. lead)


  • Lead
  • Chocolate


  • Hookworms
  • Roundworms
  • Whipworms
  • Giardia
  • Coccidia


  • Histoplasmosis


  • Parvo
  • Distemper
  • Coronavirus

Systemic Diseases

  • Pancreatitis
  • Liver Disease
  • Kidney Disease
  • Cancer


  • Salmonella
  • Clostridium
  • Campylobacter
  • Small Intestinal Bacterial Overgrowth


  • Inflammatory Bowel Disease (IBD)
  • Irritable Bowel Syndrome
  • Hemorrhagic Gastroenteritis (HGE)
  • Fiber-Responsive Diarrhea
  • Stress Colitis


  • Pancreatic Exocrine Insufficiency
  • Intestinal Obstruction
  • Intestinal Cancer

What to Do When Your Dog Has Diarrhea

Diarrhea is a nuisance at best. At its worst, it can be life-threatening for your dog.
Contact your veterinarian right away if your dog's diarrhea:

  • is accompanied by repeated vomiting, lethargy, loss of appetite, abdominal pain, generalized weakness, or fever.
  • contains large amounts of visible blood.
  • is black or tarry.
  • might be related to the ingestion of something toxic.
  • occurs in a puppy under nine months of age, particularly if vaccines were missed.
  • occurs in an elderly or medically frail animal.
  • fails to respond or gets worse despite 48 hours of symptomatic home care.

When healthy adult dogs get a simple case of diarrhea, it's often reasonable to try treating them at home. When in doubt, consult your veterinarian. Start by withholding food for 12-24 hours to give your dog's overactive digestive tract a rest. This may not be safe for small or very young dogs: consult your veterinarian.

After the fast, try giving your dog small, frequent meals of simple, easily-digested food such as boiled, low-fat chicken (remove skin) and rice. Commercial bland diets are also a good choice. Consider adding a probiotic such as lactobacillus, the "good bacteria" found in yogurt, for at least 7 days. Your veterinarian may have some specific probiotic recommendations.

Follow the sick-diet regimen until your dog has not had any diarrhea for 48 hours. Then, slowly reintroduce a healthy maintenance diet (gradually mixing it in with the bland food) over the next few days, taking care to avoid any pet foods, table scraps, or other treats that may have triggered the problem in the first place.

You'll want to confine the patient to a part of the house with easy-to-clean flooring while you wait for the new regimen to kick in. Plan frequent, short walks, but avoid lengthy or vigorous exercise while your dog is recuperating. Be courteous, and keep your dog separate from other dogs in case the problem is infectious. Pick up and safely dispose of all feces your dog leaves behind. If it's impossible to pick it up because it is too loose, flush the area with water. Use common sense with your own cleanliness and hand washing because some canine diarrheal diseases are contagious to people.

Never give any medications, including over-the-counter human medications, to your dog unless under strict instructions by your veterinarian. Inappropriate use of people medicine can make pets very sick and can result in death.

If Your Dog Ends Up at the Veterinary Clinic

You can help your veterinarian sort out your dog's problem by giving a thorough history. Be prepared with answers to the following questions:

  • When did the diarrhea begin, and how long has it been going on?
  • How many times per day does your dog have diarrhea?
  • Has your dog experienced an increased urgency, accidents in the home, or is he straining to defecate?
  • Have you seen blood or mucus in the feces?
  • What is your dog's dietary history, including diet changes or dietary indiscretions?
  • What treatments, if any, has the dog been given, and how did they work?
  • Have you noticed any other signs of illness, including vomiting, lethargy, or appetite loss?
  • Did your dog have any exposure to other animals that may have been sick?
  • Have there been any recent stressful events?
  • What is your dog's current and past vaccination status?

Your veterinarian will conduct a full physical examination, checking especially for signs of dehydration, anemia, abdominal pain, intestinal irregularities, fever, and weight loss. Your vet will most likely want to run a fecal analysis for parasites, so don't forget to bring a fresh stool sample, about the size of your thumbnail.

In simple diarrhea cases, the plan is usually straightforward. Your veterinarian is likely to prescribe a special diet and/or medication, along with a dewormer if it is indicated. Sicker dogs will need more involved workups such as lab-work, x-rays, specialized imaging, bloodwork, and fecal tests. Very sick dogs may need to be admitted to the hospital for IV fluids and intensive medical treatment. Some chronic diarrhea cases are ultimately managed through food and medication trials. Definitive diagnosis may require surgery or biopsy.

Damage Control for Canine Diarrhea

Finally, here are 3 basic steps for cleaning up the carpet after your diarrhea dog:

  1. Scoop

    Don the gloves, grab the dustpan or a strong hunk of cardboard, and pick up as much of the solid waste as you can. Avoid the temptation to rub, scrub, or spray cleansers at this stage. The stain will just penetrate deeper into your rug.

  2. Soak

    Now, saturate the stain with a liberal amount of your cleanser of choice, and wait for 5-10 minutes. Just-for-pets products with enzymatic activity can work well and are available at pet stores. Be sure to spot-test the cleanser before using it on your carpet.

  3. Scrub

    Now, with a clean, damp terrycloth rag, scrub the stain in a circular motion, working from the outside in. Be sure to use a light-colored or colorfast rag so as to avoid transferring color to your rug. If stain removal is incomplete, repeat steps two and three as needed.

Once you're satisfied with the result, use a room fan to speed the drying process. If the stain is still visible, it's time to call in the pros.

You May Also Like These Articles:

Parvo: What You Need to Know About Parvovirus in Dogs

Vomiting in Dogs

How To Tell If Your Dog Is Sick

Does a Dry Nose Mean My Dog Is Sick?

Dog Worms: Canine Intestinal Parasites

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