Abnormal stool traits usually suggest a disease, different diseases may cause blood in the stool varies, as follows: 1, black stool: black paste, shiny surface stool is often called tar-like stool, in the absence of eating special food and drugs in advance, black stool may be one of the characteristic manifestations of upper gastrointestinal bleeding, peptic ulcer, esophageal cancer, gastric cancer is a common cause, the lower gastrointestinal tract A small amount of bleeding may also appear black stool; 2, red stool: red blood stool mostly due to bleeding in the lower gastrointestinal tract (jejunum, ileum, rectum, colon), due to the shorter distance of discharge, less chemical changes, bleeding is still red, such as mixed blood and grooves in the stool, should be checked for diseases such as colon cancer, if fresh blood is only attached to the surface of the stool, it is more likely to suffer from hemorrhoids, anal fissure.