According to the Mayo Clinic, proctitis is an "inflammation of the lining of the rectum... Sexually transmitted diseases are the most common cause, but other causes include inflammatory bowel diseases, such as ulcerative colitis, and non-sexually transmitted infections." Sexually transmitted diseases that cause proctitis include gonorrhea, syphilis, cytomegalovirus, herpes, chlamydia, lymphogranuloma venereum, and amebiasis. According to the Mayo Clinic, "proctitis in general mainly affects adult males".
On March 15, 2004, Medscape published an article entitled "New Look at 'Gay Bowel Syndrome'", which commented on the 2004 journal article "Etiology of Clinical Proctitis Among Men Who Have Sex with Men" published by JD Klausner and C. Kent in the journal Clinical Infectious Diseases. The article in Medscape linked proctitis and "gay bowel syndrome" to HIV infection.[Citation Needed]