Taking medication for Helicobacter pylori (HP) that causes black bowel movements is usually a normal phenomenon, but it can also be caused by diseases such as gastrointestinal bleeding, which is an abnormal condition that requires prompt medical attention. Clinical treatment of HP infection is mainly the use of quadruple therapy, that is, a proton pump inhibitor + a bismuth + two antibiotics a total of four drugs used in combination, such as omeprazole, bismuth pectin, amoxicillin, clarithromycin. Among them, bismuth is a mucosal protective agent, and such drugs can make the tongue and stools grayish-black when taken. If bismuth is used in the treatment of HP infection, black stool is a normal physiological phenomenon. Commonly used bismuth agents are bismuth pectin, bismuth potassium citrate, etc. Black stools after taking bismuth agents can be no need to worry too much, and can return to normal after stopping the drug. During the period of taking the medicine, we should pay attention to the diet of light and easy to digest, and should also disinfect the tableware and other daily necessities to avoid cross-infection. If there is any discomfort after taking the medicine, you should seek medical treatment in time. However, if you do not take bismuth or continue to have black stools after stopping the medicine, it may be related to diet; if the black stools are accompanied by dizziness, cold limbs, blood in the stools and other symptoms, it may be caused by gastrointestinal bleeding and other diseases, it is recommended to go to the hospital as soon as possible for consultation and targeted treatment.