[Severe lower gastrointestinal bleeding in a 25-year-old patient].

Lower gastrointestinal bleeding refers to blood loss originating from a site distal to the ligament of Treitz. The aetiology varies depending on the age of patients. Excluding benign anorectal pathology in children and young people, Meckel's diverticulum, juvenile polyps and inflammatory bowel disease are the main causes. Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract, being present in about 2% of the general population. Most Meckel's diverticulum are asymptomatic and are diagnosed incidentally. The risk of complications is 4-6%, with bleeding as one of them.