Diarrhea in dogs is a common and often uncomfortable issue that can have a variety of causes. Symptoms of diarrhea in dogs include loose and watery stools, increased frequency of bathroom trips, straining to defecate, and possible presence of blood or mucous in the stool. Common causes of diarrhea in dogs include dietary changes, stress, parasites, bacterial infections, and viral infections. In order to diagnose the cause of your dog's diarrhea, your veterinarian will perform a physical examination, take a thorough history, and may order laboratory tests such as a fecal exam and/or complete blood count. Treatment of diarrhea in dogs will vary depending on the underlying cause and can include dietary changes, antibiotics, anti-diarrheal medications, or other treatments as necessary.