When people scold someone for having a bad conscience, they often say that they have a “black heart”. The medical condition of visceral blackening does exist and is called nigrosis. Clinically, this black lesion occurs in the gastrointestinal tract, especially in the large intestine, ileum, duodenum, esophagus and even gallbladder. Due to the lack of awareness of this disease, it was rarely detected and even less attention was paid to it in the past. In recent years, with the popularization of electronic endoscopy, more and more colorectal melanosis has been detected; more relevant studies have concluded that colorectal melanosis is a precancerous lesion, and it has some correlation with colorectal cancer. Therefore, the black lesion of the colon has received the attention of the medical profession and patients. What is colorectal melanosis? Negrosis of the colon is a non-inflammatory benign reversible disease characterized by pigmentation of the colonic mucosa. It is named because the mucosa of the large intestine appears brown or black under endoscopy. In modern society, people’s fast-paced life, stress, lack of exercise, poor dietary habits such as nutrient imbalance, excessive protein and lipids in the diet, insufficient dietary fiber intake, tobacco and alcohol stimulation, etc. lead to constipation has become a particularly common “fashionable disease”. In addition to the pursuit of fashion, keen to detoxification and weight loss; life many people encounter constipation is accustomed to buy some cleanse detoxification laxative tea or drugs, according to the instructions to take, few go to the hospital to consult a professional doctor to do the necessary examination. At the beginning, the effect of laxative may be good, day by day, often form drug dependence, detoxification of the dose of drugs gradually increased, without the corresponding drugs more difficult to defecate. If you go to the hospital for examination, you will find that the colon has become blackened and blackened. This phenomenon is not an isolated case in our hospital endoscopy and deserves attention. What are the causes? The pathogenesis of blackening of the colon is not clear, but research has confirmed that there is a close relationship with long-term constipation and long-term use of related laxatives. These drugs are mainly Panax Leaf, Fruit Guide Tablets, Niuhuang Detoxification Tablets, Rhubarb Soda Tablets, Intestinal Cleansing Tea, Detoxification Capsules, Aloe Vera, Cassia Seeds, etc. The main theories are: retention theory, that is, due to chronic intestinal obstruction caused by the retention of persistent stool, proteolytic products under the action of enzymes into pigment particles deposited in the intestinal mucosa. Absorption theory, which is caused by the absorption of pigment granules synthesized by intestinal bacteria in the colon or by the reduced ability of the colon to excrete pigment granules. The stimulation theory, which is caused by the stimulation of resinous substances in laxatives, which synthesize pigment particles in the colon and then deposit them in the lamina propria of the intestine and are phagocytosed. Damage theory, that is, laxatives cause damage to intestinal epithelial cells, which are phagocytosed by phagocytes in the lamina propria, and these large cell plasma pigment clusters cause the intestinal mucosa to appear black. The theory of enzyme abnormalities, that is, in some people, there are abnormal enzymes in the submucosal plexus of the intestine, and laxatives activate the activity of these enzymes, thus causing pigment accumulation and intestinal nerve dysfunction. Chronic constipation caused by long-term intestinal dysfunction, long-term low-fiber diet, gradually weakened defecation reflexes, prolonged accumulation of feces in the intestinal tract, and intestinal absorption of bacterially synthesized pigment particles. Together with active or passive administration of anthraquinone-based laxatives, these drugs contain resinous substances, which synthesize pigment particles in the colon, depositing them in the lamina propria of the mucosa, where they are phagocytosed by mononuclear cells and form black lesions. It is worth noting that there are many causes of constipation, the most common being irritable bowel syndrome of the constipated type, and many other diseases such as colorectal tumors in colorectal lesions, inflammation, redundancy, prolapse, etc. Metabolic and endocrine diseases such as diabetes, hypothyroidism, etc.; nerve and muscle diseases such as sacral nerve injury, spinal cord tumors, congenital megacolon, etc. can cause constipation, do not need to distinguish the causes, symptomatic and causal treatment, functional constipation, focus on adjusting the diet, eat more coarse grains, vegetables and fruits, less spicy and stimulating food, increase exercise, keep a happy mood, develop the habit of regular bowel movements, if you need to use drugs should also be under the guidance of If you need to use medicine, you should also use medicine under the guidance of a doctor. For organic constipation, the original cause of constipation should be treated, the surgery to surgery, can not simply take the intestinal detoxification drugs, so as not to delay the disease, endangering health.