Normal stool is yellow formed stool, dark stool may have the following reasons: 1, consider whether it is related to eating, eating food with high pigment content, such as spinach, nori, etc., the stool will become black green; 2, to consider whether the recent taking drugs caused by, such as iron, bismuth, will discharge black stool; 3, intestinal dysfunction, indigestion, inflammatory bowel disease, incomplete digestion of food will also There will be a deepening of the color of the stool; 4, must consider whether the combination of gastrointestinal bleeding, gastrointestinal bleeding will lead to continuous black stool or tarry stool. In summary, it is recommended to go to the hospital for routine fecal occult blood tests to rule out bleeding. If the deepening of stool color is caused by food or medication, usually the stool will be normal after 1-2 days of stopping the medication and there is no need to worry. If it is indigestion, you can take oral multi-enzyme tablets or probiotics to improve the symptoms of indigestion. If the stool test plus occult blood is positive, suggesting the presence of gastrointestinal bleeding, you should promptly seek medical attention and use the medication under the guidance of a doctor.