The normal color of stool is yellowish-brown, which is due to the color of bilirubin in the bile. The brown color is caused by the influence of indole and iron-containing compounds in the stool. The color of the stool can be different due to many conditions. If the stool is white in color, it is called white clay stool, which indicates that the excretion of bile is obstructed, mostly suggesting biliary obstruction, such as benign biliary stones or malignant biliary tumors or tumors in the head of the pancreas, the stool will turn white in color. In addition, excessive oil in the stool with a foul odor is commonly associated with pancreatic origin disease or malabsorption syndrome. If the stool is red, i.e. blood, consider whether there is gastrointestinal bleeding. If the stool is bright red in color, consider lower gastrointestinal bleeding, and if it is black and tarry, consider upper and middle gastrointestinal bleeding. If the stool is green, it suggests that the patient may have indigestion or gastrointestinal dysfunction or flora disorders. Therefore, the color of the stool will produce different colors depending on the disease condition.