Hemorrhagic rectocolitis is a chronic inflammatory bowel disease whose etiopathogeny is quite complex. It is considered a multifactorial disease. It is a frequent disease that affects young adults. The diagnosis is based on a combination of clinical, biological, endoscopic and histological evidence. Endoscopy plays an essential role in the diagnostic process, hence the importance of a good analysis of the elementary lesions found. The endoscopic score, calculated at the end of each colonoscopy, makes it possible to specify the severity of the current attack subjectively and to evaluate the subsequent therapeutic response.