Kidney stone surgery stool color black, consider the possible existence of peptic ulcer bleeding may, need to further investigate the condition. Kidney stone surgery is performed through the ureter or percutaneous nephrolithotomy, the stool is excreted through the digestive tract, kidney stone surgery generally does not affect the stool. The following conditions are generally considered for dark stools: 1. Digestive bleeding: Dark stools may be associated with eating colorful foods or medications, or bleeding in the digestive tract. Eating dark-colored foods such as blood products, dark-colored vegetables, or taking iron supplements, stool color will be black. 2. Gastrointestinal bleeding: Stools will be pitchy and black in color, and routine stool examination will show abnormalities such as positive occult blood. Gastroenteroscopy may reveal the presence of ulcers or even tumors in the digestive tract. 3. Post-operative stress: some patients have stress after surgical treatment, which may result in gastrointestinal ulcers and bleeding, causing abnormal stools. After the condition is clarified, the condition can be gradually controlled and stools can be normalized after taking medication to inhibit gastric acid, such as rabeprazole, under the guidance of the doctor. Black stools may be related to postoperative stress ulcers after kidney stone surgery, or other diseases such as gastrointestinal tumors, gastrointestinal ulcers and other conditions, patients are advised to further investigate.