The black color of stool after cholecystectomy has little to do with the surgery itself. Common causes include dietary factors, gastrointestinal bleeding, medication factors and so on. 1. Dietary factors: Consumption of foods with high iron content such as pig liver and duck blood, or high melanin content such as black fungus and black sesame can cause black or black-brown stools, and the color of stools can be restored to normal after stopping consumption. 2. Gastrointestinal bleeding: Gastrointestinal bleeding, especially upper gastrointestinal bleeding in esophagus, stomach and duodenum, is manifested as vomiting blood and black stools, peptic ulcer, acute gastritis and rupture of esophagogastric fundal varices are the most common, and the diagnosis can be confirmed by endoscopy. 3. Drug factors: taking iron sucrose, ferrous sulfate, bismuth potassium citrate, colloidal bismuth and other drugs will cause black stools, and the color of stools can be gradually returned to normal after stopping the drugs. There are other reasons for dark stool, it is recommended to consult a doctor in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.