Causes of stool discoloration more, mainly seen in: 1, green stool, mainly eating green vegetables, such as spinach, rape, etc., resulting in part of the food is not digested, absorbed chlorophyll from the stool, green stool, after taking Chinese medicine can also appear green stool. 2, black stool, mainly seen in eating blood products, meat food, food in the hemoglobin after digestion in the gastrointestinal tract can appear black edge. When taking metal preparations, such as colloidal bismuth pectin, ferrous succinate, the oxidation of metal preparations lead to black stools, in the case of gastrointestinal bleeding, blood in the intestinal tract after digestion is also discharged black stools. 3, red stools, mainly related to diet, such as red heart dragon fruit, the red pigment in food is not absorbed by the digestive tract, red stools appear. 4, white stools, mainly seen in bile duct obstruction caused by liver and biliary diseases, such as Liver cancer, bile duct cancer, due to obstruction of bile excretion, resulting in a reduction of fecal bileogen in the stool, appearing white clay-like stool.