Dogs get diarrhea for any number of reasons. It could be due to eating some prime specimen they discover on their walk or in the treasure trove that is the garbage can, or it could be a sign of a more serious problem, such as irritable bowel disease or colitis. This doesn't mean that every time your dog gets diarrhea you should rush him to the veterinarian immediately. There are some diarrhea cures that you can try at home first.