The causes of black stool after taking bismuth pectin are mainly divided into two kinds: drug-related and disease-related. If the case is physiological, patients can not worry, if the case is pathological, patients need to go to the hospital in a timely manner. Common causes and treatments: a. Drug-related: bismuth is a mucosal protective agent, acidic environment will produce precipitation, forming a diffuse protective layer covering the ulcer surface, after oxidation in the gastrointestinal tract will become black material, when the bismuth is discharged with the stool, the stool is black and lusterless, this is a normal physiological reasons, do not need to be too nervous, usually 2-3 days after stopping the drug black stool can disappear on its own. Second, disease-related: 1, peptic ulcer: patients with serious ulcers, ulcer surface larger, deeper, coupled with improper diet, alcohol consumption, etc. will induce upper gastrointestinal bleeding, followed by black stool. The patient can use drugs that inhibit gastric acid and enhance gastric mucosa protection, such as omeprazole, cimetidine, famotidine, aluminum thioglycollate, etc.; 2, portal hypertension: portal hypertension can lead to esophagogastric varices, which can easily lead to rupture and bleeding of esophagogastric veins when the patient has increased venous reflux blood flow, which can lead to black stool after discharge with feces. You can use posterior pituitary hormone, growth inhibitor, etc. to reduce portal pressure and perform pharmacological hemostasis, and if necessary, emergency endoscopic hemostasis to avoid aggravation of the disease; 3, tumor lesions of the digestive tract: when patients have digestive tract tumors or polyps, the rupture of tumors and polyps can lead to bleeding from the digestive tract and black stools. Patients should go to the hospital for e-colonoscopy in time to avoid delaying the disease. Early surgical resection is the main focus, and later chemotherapy and radiotherapy can be combined to obtain a longer survival time.