10/12/2025
Diarrhea
Diarrhea: Worry or wait?
If loose stool lasts more than two days, call the vet
Diarrhea is no fun for you or your dog, but the good news is that most cases resolve on their own. Mild cases are usually uncomplicated, and the dog is otherwise happy and normal.
“Many cases of diarrhea in dogs and cats are mild and self-limiting,” says Dr. Meredith Miller, associate clinical professor of small animal medicine. “If a pet stops eating, is lethargic, the diarrhea is black or tarry in quality, there is associated vomiting, or the diarrhea doesn’t resolve in 48-72 hours then veterinary care should be sought.”
Under normal conditions, water is absorbed through your dog’s gastrointestinal (GI) tract to be used within the body. When they have diarrhea, everything passes through too quickly, and excess water is expelled along with the waste products. Over time, this can cause dehydration. Vomiting, in addition to diarrhea, further accelerates dehydration. Dehydration causes electrolyte imbalances in the body, puts extra strain on the kidneys and can lead to organ failure and death.
Anorexia and lethargy indicate that your dog is not feeling well. This may just be due to gastrointestinal discomfort (no one wants to eat when their guts are twisting), but these symptoms can also accompany a variety of illnesses. If your dog does not bounce back to normal quickly, veterinary attention should be sought.
Black stool, officially called melena, is caused by partially digested blood coming out in the f***s. The source of the blood could be in the upper GI tract, the mouth or even the respiratory tract. These bleeds can be caused by a foreign body, infections, inflammation, trauma, tumors or ulcers.
Bland diet
“Mild cases of diarrhea in both cats and dogs can be treated at home by feeding a bland diet such as boiled chicken or low-fat hamburger, and white rice,” says Miller. Cooked pasta is another option. These foods are easy to digest, so they give your dog’s GI tract a break.
The exception to this rule would be if your dog has an allergy or intolerance to one of these foods — if that is the case, avoid the problematic ingredient to prevent further upset. Another tip is to start by withholding all food for 12-24 hours, then introduce the bland diet. Note: These bland diets are not appropriate for long-term feeding as they are not nutritionally balanced.
If your dog is experiencing diarrhea after switching to a new food, it may be that you made the switch too quickly. Go back to feeding the original diet until their stools have firmed up again, then restart the transition process but go more gradually. For example, instead of feeding 75% the original diet and 25% the new diet on the first day, 50% of each on the second day, and then 25% original and 75% new on the third day, spread the transition over a week or two so that your dog’s GI tract has more time to adjust.
“Owners should avoid excessive treats or rich food until the diarrhea resolves,” says Miller.
If diarrhea continues for more than a day or two, schedule an appointment with your veterinarian to help your dog get some relief.
