Ms. Chen, 37 years old. She was admitted to the hospital with “anal pain with blood in the stool for 7 months after radiotherapy for cervical cancer for more than 1 year”. The patient had undergone radiation therapy for cervical cancer more than one year ago, and the effect of cervical cancer after radiation therapy was remarkable, and no recurrence was seen in regular review; however, recurrent anal pain began to appear 7 months ago, which was getting worse day by day and affected her life and rest. After treatment with enemas in several hospitals, the effect was not good, and the anal pain and blood in stool still recurred. So he came to our hospital for treatment. Wang Lei, Department of Gastroenterology and Anorectal Surgery, The Sixth Hospital of Sun Yat-sen University After admission, he was examined by colonoscopy, which showed “diffuse edema of the rectal mucosa, especially in the lower rectum, mucosal edema and bleeding, mucosal erosion in the anterior wall of the lower rectum, with elevated lesions, brittle and easy to bleed”, and pathological biopsy of the rectal lesion showed “rectal The pathological biopsy of the rectal lesion showed “chronic inflammation of the mucosa, submucosal vascular dilatation, congestion, focal hemorrhage, and no tumor”. The admission diagnosis was “1, radiation proctitis 2, after radiotherapy for cervical cancer 3, after radiotherapy for cervical cancer”. After admission, the patient was discharged from the hospital with 4% formalin rectal mucosal cautery to stop the hemorrhage. One month after discharge, the patient developed blood in the stool again, and was readmitted for 4% formalin rectal mucosal cautery hemostasis, after which the patient’s blood in the stool was significantly relieved. The patient did not have any further blood in the stool at 2 years of follow-up. Summary: Formalin produces thrombus in the mucosal layer of neovascularization by making protein coagulation mechanism, thus playing a superficial role in hemostasis. Local application of formalin is more effective in the treatment of persistent radiation proctitis bleeding, and has the advantages of low price, high practicality, and repeated treatment if the effect is unsatisfactory.