Ordinary proctitis after 3 months cancer may be caused by repeated proctitis inflammation stimulation, such as bacterial infection, amoebic dysentery and so on. 1. Bacterial infection: proctitis caused by bacterial infection will have symptoms such as loss of appetite, nausea and vomiting, acute and severe symptoms, bloody stools, etc. Repeated bacterial infections will worsen the condition, resulting in intestinal stenosis, proliferative lesions, etc., which will lead to cancer. 2. Amebic dysentery: it is a proctitis caused by amebas parasitized in the colon by lysed tissues, which will cause abdominal pain, diarrhea and other symptoms, if the treatment is not timely, the aggravation of the condition may cause intestinal perforation, intestinal hemorrhage and other complications, and it may also cause proctitis cancer. Therefore, patients with common proctitis should go to regular hospitals as soon as possible to find out the cause of the disease, and under the guidance of professional doctors, give standardized treatment as early as possible to avoid delaying the condition and causing adverse consequences.