One of the most common problems we see in veterinary medicine is gastrointestinal (GI) upset/diarrhea.

Please remember this information does not replace proper vet care.

You may not be able to totally prevent diarrhea, but knowing as much as possible about it might help limit the number times your dog has one of these unpleasant episodes and reduce the duration when the runs do come.

The Canine Digestive System

There are significant differences between the way dogs and people digest food.

Human jaw shape and salivary enzymes, for example, will start breaking down a morsel in the mouth. Dogs, on the other hand, have mouths and jaws made for tearing, crushing, and wolfing food down. Their salivary enzymes are mostly designed to kill bacteria, which is why they can tolerate items that would send their human companions to the hospital.  Food travels rapidly down the canine esophagus and enters the stomach in chunks, where most digestion takes place. Canine stomach acids are about three times stronger than those of humans, so they can digest food that is pretty much intact. Under normal circumstances, transit time from mouth through the small and large intestines should be under 10 hours, producing a firm, well-formed stool at the end.

Dirty Dozen—Top 12 Causes of Doggie Diarrhea

Many things can disrupt this well-balanced system, causing diarrhea or, less frequently, constipation. Some things, like eating too much grass, are not serious at all. Others can be a sign of a life-threatening problem, such as an indigestible object (like a rock) lodged in the stomach, or a disease like cancer.

There are many reasons why a dog may develop loose stools, but most cases may be attributed to one of these 12 triggers:

1. Dietary indiscretion: Eating too much, eating garbage, or spoiled food. There’s actually a name for it in veterinary circles—“garbage toxicosis” or “garbage gut.”
2. Change in diet: It may take a few days for a dog’s digestive system to adapt to new proteins. That’s why many dog-food manufacturers recommend that you go slow when you switch from one brand of food to another.
3. Food intolerance
4. Allergies
5. Parasites: Most of these will cause illness in puppies or in adults with weak immune systems:
   1. Roundworms
   2. Hookworms
   3. Whipworms
   4. Coccidia
   5. Giardia
6. Poisonous substances or plants
7. Swallowing an indigestible foreign body, like a toy or a dozen or more socks
8. Infections with common viruses such as:
   1. Parvovirus
   2. Distemper
   3. Coronavirus
9. Bacterial infections, such as salmonella
10. Illnesses, such as kidney and liver disease, colitis, inflammatory bowel disease, and cancer
11. Antibiotics and other medications
12. Stress or emotional upset

Loose or liquid, frequent stools are the most common symptoms of diarrhea in dogs. Other signs include flatulence, blood or mucus in stool, changes in volume of stool and straining to defecate. Lethargy, dehydration, fever, vomiting, decreased appetite, weight loss and an increased urgency to defecate may also accompany diarrhea.

Bring your dog to the vet if his diarrhea continues for more than a day, or if you observe lethargy, vomiting, fever, dark-colored or bloody stools, straining to defecate, decreased appetite or unexplained weight loss. Contact your veterinarian immediately if you notice your puppy has diarrhea, as it can be an important indicator of serious diseases in young dogs.

Information gathered from WebMD and the AKC