Bismuth is currently used in the treatment of stomach ulcers, including H. pylori infection. The commonly used colloidal bismuth pectin or gastric bismuth magnesium, both of which have the potential for blackened stools. Because the color of colloidal bismuth pectin drug was also a little black, if the stool is simply black, there is no bloody taste, and there is no bad smell. This can be judged as the black stool caused by the drug, and even the oral mucosa, the mucosa of the tongue will have black symptoms. If you have ulcers or bleeding ulcers, it is recommended that you do not use colloidal pectin bismuth for a short period of time. If you have to use colloidal pectin bismuth and then appear black stools, it is recommended to improve the stool routine, to clarify whether there is occult blood in the stool routine, that is to say, to clarify whether there are symptoms of gastrointestinal bleeding. If there are no symptoms of gastrointestinal bleeding, stool routine and occult blood are normal and negative. In this case, when stop using bismuth, the black stool will be slowly relieved, with the metabolism of the drug will also gradually disappear.