Diarrhea, medically known as diarrhea, is a self-protective mechanism of the body that helps to expel toxins and has a protective effect on the body. Diarrhea is defined as having more than 3 bowel movements per day, or thin stools due to increased water in the stool, or having more than 200 grams of stool per day. Diarrhea can be divided into acute (less than 4 weeks) and chronic (more than 4 weeks) diarrhea according to the duration of the disease. Acute diarrhea is mainly seen in acute intestinal infections and food poisoning, and generally acute diarrhea has a clear etiology, comes quickly and heals relatively quickly, so we will not go into details here. First look at why there is diarrhea? 1, exudative diarrhea: when the integrity of the intestinal mucosa is damaged by inflammation, ulcers and other lesions, resulting in a large amount of exudation and diarrhea, which can be divided into two categories: infectious and non-infectious. Exudative diarrhea is characterized by feces containing exudate and blood, lesions in the colon, especially the left colon, causing more fleshy purulent stools, and alkaline fecal pH. 2. Secretory diarrhea: diarrhea caused by excessive secretion of water and electrolytes from the stomach and intestines. Secretory diarrhea has the following clinical characteristics: ① excretion of large amounts of watery stool, which can be up to several liters per day; ② stool containing large amounts of electrolytes; ③ stool without pus and blood; ④ diarrhea does not stop after fasting; ⑤ generally no abdominal pain. 3, osmotic diarrhea: due to the large amount of non-absorbed solutions (non-electrolytes) in the intestinal lumen, the effective osmotic pressure in the intestinal lumen is too high, which prevents the absorption of water and electrolytes by the intestinal wall. Osmotic diarrhea has two clinical features: (i) the diarrhea stops after fasting or after stopping the intake of non-absorbed substances; (ii) the electrolyte content of the stool is reduced by laboratory analysis. In osmotic diarrhea, water is secreted into the intestinal cavity due to the hypertonic state of the intestinal cavity caused by solutes that cannot be absorbed, and electrolytes are secreted less. 4, abnormal intestinal movement: when the intestinal movement is too slow or too fast, it can cause diarrhea; weakened movement can make the small intestine bacteria multiply too much, damaging the intestinal mucosa, bacteria also decompose and combine bile salts, causing lipid diarrhea; when the intestinal peristalsis is too fast, the intestinal contents and small intestinal mucosa can not fully contact, incomplete absorption, a large number of small intestinal contents into the colon, resulting in diarrhea. The clinical characteristics are: ①Dilute or watery stool without or with few inflammatory cells. (iii) Hyperactive bowel sounds. ③It may be accompanied by abdominal pain. What diseases can cause diarrhea? 1, enterogenic diarrhea: This is the most common cause of chronic diarrhea, including various inflammatory diseases of the intestine such as chronic bacterial dysentery, chronic amebic dysentery, inflammatory bowel disease, etc., various intestinal tumors such as colorectal cancer and intestinal dysbiosis, etc. The following pathogens often cause chronic diarrhea: chronic amoebic dysentery, chronic bacterial dysentery, intestinal tuberculosis, pear-shaped flagellosis, schistosomiasis, and intestinal candidiasis. Some patients may develop irritable bowel syndrome after infectious diarrhea. Non-infectious inflammatory diseases of the intestine include: inflammatory bowel disease (Crohn’s disease and ulcerative colitis), radiation enteritis, ischemic colitis, diverticulitis, and uremic enteritis. Small intestine malabsorptive diseases include: ① pancreatic digestive enzyme deficiency, such as chronic pancreatitis, pancreatic cancer and pancreatic fistula. (ii) disaccharidase deficiency, such as lactose intolerance, etc. (③) Bile drainage obstruction and insufficient bound bile salts, such as extrahepatic bile duct obstruction, intrahepatic cholestasis, and small intestinal bacterial excess (blind collaterals syndrome). Reduced absorption surface of small intestine such as excessive small bowel resection (short bowel syndrome), proximal small bowel colonic anastomosis or fistula, etc. 2, gastrogenic diarrhea: including diarrhea caused by gastric diseases and the return of intestinal contents or bile into the stomach. The main manifestations are corrosive dyspepsia, increased number of stools in the morning or after meals, more paste-like stools than watery stools, more exhaust, and odor, alkaline reaction of stools, and microscopic examination of transverse muscle fibers. The causes of diarrhea are: ① the stomach is not fully digested food (mainly protein) in the intestine caused by corrosive indigestion; ② after gastric surgery, a large amount of undigested food in the stomach dumped into the intestine, causing an increase in intestinal peristalsis; ③ gastric acid secretion or lack of influence on the exocrine function of the pancreas, resulting in the occurrence of steatorrhea. 3, pancreatic origin diarrhea: often occurs after chronic pancreatitis, pancreatic cancer, cystic fibrosis and extensive pancreatectomy. Chronic pancreatitis often has recurrent epigastric pain, symptoms of inadequate pancreatic exocrine secretion, such as intolerance of fatty foods, epigastric fullness and discomfort after eating, diarrhea, malnutrition, and weight loss. Stool 3-5 times a day, stool volume, pale and oily, malodorous, polygas, microscopic fat globules, but also incompletely digested muscle fibers. 4. Hepatobiliary-derived diarrhea: Diarrhea of different degrees can occur in portal hypertension of cirrhosis, which is related to digestive and absorption dysfunction caused by stasis in the gastrointestinal tract. Patients with hepatocellular carcinoma often have diarrhea, poor digestion, indigestion, nausea, vomiting and other symptoms, which are easily ignored due to lack of specificity. In patients with long-term cholestatic jaundice and severe liver disease, reduced bile formation or poor drainage can lead to poor digestion and absorption of fat. 5, systemic disease diarrhea: common in diabetes, hyperthyroidism, autoimmune diseases such as lupus erythematosus, dermatomyositis, scleroderma and rheumatoid arthritis, etc. 6, functional diarrhea: functional diarrhea is a syndrome of continuous or recurrent discharge of loose stools or watery stools without abdominal pain or abdominal discomfort. Diarrhea without bacterial, viral or parasitic infection is generally caused by gastrointestinal dysfunction. The occurrence of this disease may be associated with psychological factors, abnormal intestinal motor-sensory function, and autonomic dysfunction. Various tests have failed to find organic lesions that cause diarrhea. Why do some people often have diarrhea? 1, gastrointestinal dysfunction: this situation is most common among young adults, mainly with the contemporary young people do not pay attention to dietary health is directly related. Like to eat heavy food, especially like to eat high fat or spicy stimulating food, will also lead to the onset of chronic diarrhea. Chronic diarrhea can also occur in people who have poor eating habits, who often overeat, or who alternate between hot and cold foods. Digestive system dysfunction can also affect the digestion of the daily diet, resulting in the phenomenon of chronic diarrhea. 2, digestive malabsorption: characterized by foul-smelling stools, oil droplets and undigested food in the stool, large amounts of diarrhea, often with significant weight loss and malnutrition. The causes are absorption dysfunction of the small intestine, insufficient secretion of pancreatic juice or bile, and short residence time of food surimi in the intestine. People with chronic pancreatitis, cholecystitis, hyperthyroidism, or a history of gastrointestinal surgery are prone to steatorrhea. 3, chronic inflammation of the intestine: including chronic dysentery, intestinal tuberculosis, schistosomiasis, etc., as well as inflammatory bowel disease, ischemic enteritis, radiation enteritis, etc. The nature of the stool can be specific depending on the cause of the disease, such as rotavirus enteritis egg-shaped stool, dysentery and ulcerative colitis will appear pus and blood stool. 4, intestinal flora dysbiosis: under normal circumstances, the intestinal flora according to a certain proportion of the combination, the bacteria between the mutual constraints, interdependence, in quality and quantity to form an ecological balance, once the internal and external environment of the body changes, especially the long-term application of broad-spectrum antibiotics, sensitive intestinal bacteria are inhibited, not inhibited bacteria and multiply, thus causing dysbiosis. The disease to severe diarrhea or chronic diarrhea as the main clinical manifestations of diarrhea is mostly light yellow-green watery stool, sometimes such as egg flower-like. In recent years, due to the popular use of refrigerators, some families store a large amount of meat and vegetables, too long storage makes food deterioration, after consumption caused by intestinal flora imbalance, resulting in vomiting, diarrhea.