Cap-assisted endoscopic sclerotherapy (CAES) is a new interventional therapy for internal hemorrhoids and rectal prolapse under colonoscopy. However, the long-term efficacy and safety of CAES in the treatment of internal hemorrhoids and rectal prolapse are still not clear due to the lack of large sample studies. Therefore, a nationwide multi-center, large sample, prospective and cohort study was designed to evaluate the efficacy and safety of CAES in the treatment of internal hemorrhoids and rectal prolapse, to provide reliable evidence for popularization of this minimally invasive technology.