Editor,—We published in 1999, to our knowledge, the first description of diversion colitis appearing to trigger instream ulcerative colitis (Gut1999;44:279–282). We have recently encountered a fourth patient with the same rare condition.

A 66 year old non-smoking white man presented in 1997 with large bowel obstruction. His mother had died of colorectal carcinoma at the age of 71 years. There was no …