What are the causes of diarrhea? There is no specific issue that causes diarrhea, it could be caused by many different reasons, ranging from food poisoning, upset stomach, stress, anxiety, diseases and other more serious issues. In this video Dr. Fazil explains the most common possible causes and what treatment options are available to not only treat the diarrhea when it occurs but to find the root cause of it and treat it. He goes into detail how to treat diarrhea at home and when to seek medical attention before it gets to a point where minimal treatment will be effective.