Lack of sleep does not usually cause black stools. If lack of sleep is accompanied by black stools, it may be due to physiological reasons such as eating duck blood, or it may be caused by upper gastrointestinal bleeding. If you have recently been sleep deprived while eating animal blood products such as duck blood, the color darkens under the action of gastric acid and other intestinal substances, leading to black bowel movements. If sleep deprivation is accompanied by taking non-steroidal anti-inflammatory drugs such as aspirin and antiplatelet drugs such as Tegretol, which inhibit platelet agglutination and cause gastrointestinal bleeding, resulting in dark-colored stools. If accompanied by esophagitis, peptic ulcer, portal hypertension esophagogastric fundal varices rupture and other upper gastrointestinal bleeding, blood in the gastrointestinal tract for a long time, after the reaction, will also lead to black stool color. If black stools occur with frequent sleep deprivation, and physiological reasons such as eating are ruled out, you should seek medical attention in time and under the guidance of your doctor to avoid delays.