Diversion colitis is an inflammation of the colon which can occur as a complication of ileostomy or colostomy, often occurring within the year following the surgery. It also occurs frequently in a neovagina created by colovaginoplasty, with varying delay after the original procedure. Despite the presence of a variable degree of inflammation the most suggestive histological feature remains the prominent lymphoid aggregates. A foul smelling, mucous rectal discharge may develop from the inflamed mucosa of the distal, unused colon. Diversion colitis is an inflammation of the colon which can occur as a complication of ileostomy or colostomy, often occurring within the year following the surgery. It also occurs frequently in a neovagina created by colovaginoplasty, with varying delay after the original procedure. Despite the presence of a variable degree of inflammation the most suggestive histological feature remains the prominent lymphoid aggregates. A foul smelling, mucous rectal discharge may develop from the inflamed mucosa of the distal, unused colon. The diagnosis cannot be safely reached without knowing the clinical story. In many milder cases after ileostomy or colostomy, diversion colitis is left untreated and disappears naturally. If treatment is required, possible treatments include short-chain fatty acid irrigation, steroid enemas and mesalazine.