Drinking Pu-erh tea and then passing black stools may be due to physiological reasons such as the black-brown liquid of the tea, eating animal blood, or pathological reasons such as bleeding from gastric ulcers. 1. Physiological reasons: Pu-erh tea will appear black-brown liquid after steeping, after drinking a lot of Pu-erh tea, in the gastrointestinal tract and food residue mixing will make the color of the stool deepen, it looks like black stools, stop drinking tea after the color of the stool can be changed. If at the same time eating a lot of pig blood, duck blood and other animal blood, animal blood in the iron element changes after the discharge of the body, will also appear stool black. 2. Pathological reasons; the black color of stool may also be gastric ulcer, esophagogastric fundal varices rupture bleeding and other gastrointestinal bleeding, if it is a chronic bleeding or bleeding is small, the blood in the gastrointestinal tract for a long time after the reaction, the color of the bowel movement will change to black. Drinking Pu-erh tea defecation color black, if you exclude eating and other physiological reasons, you should promptly consult a doctor to find out the cause, under the guidance of the doctor for treatment, so as not to delay the condition.