What is the cause of blue stool?

The color of defecation is yellow, because there are fecal bile original through bacterial fermentation, so the color of stool is yellow. But if the stool is black, generally consider gastrointestinal bleeding or eating certain foods, eat blood sausage, chocolate, and some drugs, such as bismuth or iron, can also cause stool black. If the stool is green, consider whether to eat green vegetables, or some drugs, such as spirulina, aloe capsules, etc. can also cause green stools. If the stool is green with loose stools, gruel-like stools or mushy stools, consider whether the patient shows symptoms of indigestion. If the patient is accompanied by abdominal pain or nausea and vomiting in addition to green stools and diarrhea, it is recommended that the patient check electronic colonoscopy to rule out organic intestinal lesions.