There are many reasons for black-green stools, the common ones are mainly the following: 1, may have a relationship with diet, eat foods containing chlorophyll or high-fiber foods, it may lead to black-green stools, generally do not need to deal with. 2, indigestion, can appear black-green stools, stools are not shaped, soup-like stools, or there are undigested food residues, etc., generally need to be anti-inflammatory, anti-diarrheal, rehydration and other treatment, diet drink millet porridge, eat buns, good rest, 3, taking drugs may also appear black green stools, such as long-term use of laxatives, as well as bismuth, traditional Chinese medicine, proprietary Chinese medicine, can appear black green stools. It is not recommended that patients with constipation take laxatives for a long time, which can easily lead to black lesions of the intestines.