Hematochezia is a form of blood in stool, in which fresh blood passes through the anus while defecating. It differs from melena, which commonly refers to blood in stool originating from upper gastrointestinal bleeding (UGIB). The term derives from Greek αἷμα ("blood") and χέζειν ("to defaecate"). Hematochezia is commonly associated with lower gastrointestinal bleeding, but may also occur from a br... Wikipedia