The color of stool does not usually change after taking Yunnan Baiyao, but it may change if there is some kind of disease. If the color of the stool is black and tarry after taking Yunnan Baiyao, it is often indicative of gastrointestinal bleeding. For example, peptic ulcer, i.e. gastric ulcer and duodenal ulcer bleeding can lead to such tarry stools, as well as intestinal lesions, such as right-sided colon cancer can also lead to tarry stools. If the color of the stool is clay-colored after taking Yunnan Baiyao, it is often suggestive of biliary obstruction, and yellow staining of the skin and sclera often occurs. Normal stools are usually yellow, if there can be a tarry color, or the appearance of clay white color, should be vigilant, if necessary, timely to the hospital, a clear diagnosis.