Normal stool color is yellowish brown. Normal stool color is yellowish-brown, usually formed soft stools with no special odor, and the frequency of stools is about 1 to 2 times a day or 1 to 2 days to relieve once. Because the character of stool is greatly influenced by the type, nature and amount of food, as well as by some medications such as colloidal bismuth and parasites such as roundworm infections, the character of stool is of great value in the diagnosis of digestive and parasitic diseases. Stools that are black in color, especially shiny black, called tarry stools, often indicate the possibility of gastrointestinal bleeding. White, clay-colored stools are often indicative of biliary obstruction. Normal stools are usually yellow, if there is a tarry color, or the color of clay white, should be taken seriously, if necessary, go to the hospital in a timely manner, a clear diagnosis.