Question: reasons a dog has diarrhea?
Answer: Change in Kibble. A sudden change in diet can upset your dog's stomach and intestinal tract, leading to diarrhea. ... 
Ate Spoiled Food. ... 
Bacterial Infection and Viral Diseases. ... 
Intestinal Parasites. ... 
Ate Toxic Substance. ... 
Allergic Reaction. ... 
Ate a Foreign Object. ... 
Irritable Bowel Disease.