Five Types and Characteristics of Diarrhea Diarrhea refers to a digestive system disease in which the amount of stool increases, the stool is semi-liquid or watery, and is accompanied by symptoms such as abdominal fullness and abdominal pain. Diarrhea can be divided into five types according to its nature. 1. Acute infectious diarrhea Acute infectious diarrhea is generally caused by bacteria, viruses, molds, etc., and the course of the disease usually lasts for 3 years.