Cause #3 - Gastrointestinal Infection/Disease
If your dog has diarrhea, is losing weight, has blood in stool, has bad breath, constipated, doesn't want to eat, vomits, or the abdominal area has enlarged, it could be a sign of gastrointestinal infection. It should not be taken lightly. Although fowl breath is just a symptom, this could lead to a more serious issue.