Diarrhea is a common symptom, commonly known as “diarrhea”, which means that the number of bowel movements significantly exceeds the usual frequency, the stool is thin and watery, and the daily volume of bowel movements exceeds 200g, or contains undigested food or pus, blood or mucus. Diarrhea is often accompanied by a feeling of urgency to defecate, anal discomfort, and incontinence. There are two types of diarrhea: acute and chronic. Acute diarrhea has a rapid onset and lasts for 2 to 3 weeks. Chronic diarrhea refers to recurrent diarrhea with a duration of more than two months or an interval of 2 to 4 weeks. 1, occupation: farmers are often in contact with manure, intestinal bacteria, parasitic infections are higher; farmers or fishermen in the middle and lower reaches of the Yangtze River often barefoot plowing, easy access to epidemic water, diarrhea is mostly associated with schistosome infection. 2, past history: chronic bacillary dysentery patients have a past acute onset; malabsorption syndrome patients have a history of chronic intestinal infections or chronic intestinal absorption disorders; blind collaterals syndrome, short bowel syndrome, major gastrectomy, cholecystectomy diarrhea patients, all have a history of surgery; radiation colitis patients have received radiation therapy, or a large number or long-term radiation exposure history; Crohn’s disease, ulcerative The majority of patients have a history of past illnesses, such as Crohn’s disease, ulcerative colitis, systemic lupus erythematosus and systemic scleroderma. 3, concomitant symptoms: if the lesion is located in the rectum or sigmoid colon, the symptoms are generally early, mostly diarrhea, frequent bowel movements, a sense of urgency, each stool volume is small, or even only some gas or mucus, and no fecal matter. If the stool is dark, thin, mucus-like, may or may not contain blood visible to the naked eye, and the odor is not heavy. If accompanied by abdominal pain, it is mostly located in the lower or left lower abdomen, with persistent episodes that can be relieved after defecation. If the lesion is located in the small intestine, can be bleeding diarrhea symptoms, not accompanied by a sense of urgency, stool often presents a light color and quantity, that is, watery stool, more foam or greasy feeling obvious, malodorous, no blood and pus visible to the naked eye, but often undigested food particles or debris; if the which has abdominal pain, it is mostly around the navel or confined to the right lower abdomen, often colic, intermittent episodes, hyperactive bowel sounds. 4, the number of diarrhea: if the patient occurs acute diarrhea, stool 24 hours diarrhea up to 10 times ~ dozens of times, mostly for the infection caused by secretory diarrhea, such as cholera, pathogenic E. coli enteritis. If chronic diarrhea, may be caused by gastrointestinal tumors such as pancreatic cholera, carcinoid syndrome, etc. 5, stool traits: stool is mucus, purulent bloody stool, mostly intestinal inflammation, exudation, ulceration and hemorrhagic lesions, such as bacterial dysentery, chronic ulcerative colitis, Crohn’s disease, rectal cancer, sigmoid colon cancer and other exudative diarrhea or tumors. If the total amount of stool is large, thin and unformed, containing a lot of undigested food, that is, “what to eat and what to shit”, and the diarrhea symptoms are relieved after fasting, it is mostly osmotic diarrhea caused by digestive malabsorption, which is common in malabsorption syndrome. It is mainly caused by osmosis diarrhea due to malabsorption syndrome, etc. The stool is thin or watery, with few white blood cells, accompanied by intestinal rumbling and paroxysmal abdominal pain, mainly around the umbilicus. Diseases such as hyperthyroidism, carcinoid syndrome, hyperaldosteronism, etc.