The steps of clinical thinking in the diagnosis of diarrhea are etiology, course and accompanying symptoms. Diarrhea commonly known as diarrhea usually refers to an increase in the number of bowel movements, thin and heavy stools may be accompanied by abdominal pain and malaise. 1. Etiology: according to the color of the stool and stool routine can be divided into infectious and non-infectious. 2. Duration: According to the duration of diarrhea, it can be divided into acute (acute onset of disease, within 2 to 3 weeks, usually infectious, accompanied by fever and dehydration, etc.) and chronic (duration of the disease ≥ 2 months or recurrent, usually non-infectious). 3. Accompanying symptoms: manifested as bloody stools and pus-blood stools, stool routine with white blood cells and red blood cells, etc. Treatment is based on antibiotics; yellowish stools with fat particles for dyspepsia treatment of digestive and regulating bacterial imbalance is based on. If there is any discomfort, we recommend that patients go to a regular hospital, do not blindly self-treatment in order to avoid delaying the condition.