After taking compound Lactobacillus acidophilus tablets the stool is black, consider that it is not related to Lactobacillus acidophilus tablets medication, and the possible causes include dietary factors, other medication factors, and gastrointestinal bleeding. Compound Lactobacillus acidophilus tablets are mainly composed of various probiotics, with intestinal flora regulation, suitable for intestinal dysbiosis caused by intestinal flora dysregulation of intestinal dysfunction, such as mild acute diarrhea, etc., therefore, consider that the blackness of the stool is not very relevant to the use of compound Lactobacillus acidophilus, and other reasons need to be investigated. 1. Dietary and medication factors: eating a lot of animal blood products and other iron-rich foods, iron, bismuth potassium citrate and other drugs, after digestion and absorption, will lead to dark stools, not accompanied by other discomforts, and can be returned to normal after stopping eating. 2. Gastrointestinal bleeding: patients using Lactobacillus tablets themselves have gastrointestinal diseases, the appearance of black stools does not exclude the possibility of gastrointestinal bleeding, may be accompanied by dizziness, fatigue, vomiting blood, abdominal pain and other discomforts, if you exclude the possibility of diet and other medications, it is recommended to consult a doctor in time, blood and stool routine and other tests, to investigate the existence of gastrointestinal bleeding. Taking Lactobacillus acidophilus tablets does not usually lead to black stools, and it is recommended that patients take into account their own diet, medication and symptoms to investigate whether there is gastrointestinal bleeding, and seek medical treatment in a timely manner.