Normal stool is yellow, but taking certain medications can cause a change in stool color. Some drugs that change the color of the stool are normal and do not affect the continued use of the drug. The drugs that make the stool white are antacids (aluminum hydroxide, etc.); the drugs that make the stool yellow or green are anthraquinones (rhubarb, etc.), indomethacin (anti-inflammatory pain), etc.; the drugs that make the stool black are bismuth preparations (such as astringent antidiarrheal and gastric mucosa protective drug bismuth potassium citrate, alkaline bismuth nitrate, colloidal bismuth pectin, colloidal (state) bismuth potassium tartrate, colloidal bismuth subcitrate, bismuth aluminate), ferrous salts (such as the treatment of anemia ferrous sulfate, ferrous fumarate, ferric ammonium citrate, ferrous lactate, etc.) and medicinal charcoal used for adsorption and antidiarrheal; drugs that make the stool red include rifampin, enboviramine (pinch); drugs that make the stool clay-like and gray include barium sulfate used for gastrointestinal imaging. Some drugs are irritating to the gastrointestinal tract, causing blood in the stool or black stools, tarry stools, such as aspirin, pterostilbene, hydroxy pterostilbene, warfarin, etc. If taken for a long time, it can cause bleeding in the gastrointestinal tract, which is an adverse reaction to the drug, which should be discontinued immediately. When you find that the stool changes color, you should first consider the medication factors, if not related to medication, you should also consider dietary factors (the presence of consumption of animal blood products such as duck blood), after excluding these factors, you should go to see a doctor for relevant examinations, in order to early detection of disease and timely treatment.