Canine diarrhea isn't ever going to smell like roses, but if your dog experiences an episode of exceptionally smelly diarrhea, take him to the vet for an examination. If he's a puppy, get him to the vet immediately. Foul-smelling diarrhea can signal diseases potentially fatal to puppies. Always bring a stool sample to the vet for testing.
Smelly diarrhea might indicate that your dog is infested with giardia, a protozoal parasite. Canines with giardia experience sudden, especially bad-smelling diarrhea, which might appear somewhat green or contain blood. Mucus is often present in the feces. Some dogs might vomit, and lethargy is common. Puppies can become dehydrated quickly. If fecal testing show giardia, your vet might prescribe the antibiotic metronidazole for treatment. Since dogs can spread giardia to humans, disinfect your dog's living spaces with dilute bleach and keep him away from people with compromised immune systems until fecal testing shows he is no longer carries the parasite.
Exocrine Pancreatic Insufficiency
Exocrine pancreatic insufficiency results when the pancreas no longer produces sufficient amounts of digestive enzymes. Symptoms include smelly, pale diarrhea. Other symptoms of exocrine pancreatic insufficiency include constant hunger and weight loss. German shepherds are particularly prone to the disorder, which strikes the breed at a relatively young age. Other dogs are generally middle-aged or elderly with exocrine pancreatic insufficiency occurs. Fortunately, after diagnosis, most dogs do well on a supplement containing digestive enzymes, which they must eat for the rest of their lives. Your vet might recommend dietary changes as well.
Coronavirus in Dogs
Most dogs will get over a bout with canine coronavirus, an intestinal infection. However, it can prove fatal to puppies, who quickly become dehydrated. A telltale sign of coronavirus is passing yellowish, particularly foul-smelling, sometimes bloody diarrhea. Other symptoms include vomiting, appetite loss and depression. While adult dogs might recover in a few days, a puppy can require intravenous fluids to stave off dehydration. Your vet might prescribe medication to stop diarrhea and vomiting.
Parvovirus in Dogs
Bad smelling diarrhea is just one sign of parvovirus, an often deadly disease. While a parvovirus vaccine is one of the core canine inoculations, the initial shot is not generally given to puppies before the age of 6 to 8 weeks, with two booster shots before the dog is 4 months old. The adult dog receives another booster one year later. Unvaccinated dogs or those who did not receive the entire vaccination series are at highest risk. Other symptoms include appetite loss, vomiting and weakness. There's no cure for parvo, but some afflicted dogs survive with intense supportive care. This includes intravenous fluids, antibiotics, medications for vomiting -- all done in a veterinary hospital. It's not a disease that an owner can treat at home.