To find out the cause of diarrhea black watery, can be due to overeating, overeating spicy and cold stimulation, etc. indigestion, may be caused by bacteria, viruses and other infections, sudden changes in mood. Ask whether there are other complications, such as abdominal pain, nausea, vomiting, etc., after diarrhea symptoms have no relief, there are no special parts of the pressure and rebound pain, black watery has no occult blood, there is no combination of other diseases, it is best to go to the hospital for examination. These symptoms are mainly related to the digestive system.