LETTER Oral contraceptives and Crohn’s disease Dear Sir,

Khalili et al,1 which confirms the association between oral contraceptive use and increased risk for Crohn’s disease in two impressively large cohorts. When we studied this some years ago, we found that oral contraceptive use associated much more strongly with isolated colonic Crohn’s disease than with small intestinal disease.2 Further analysis of our cases and those previously published as case reports suggested that most of these had non– granulomatous colitis—the diagnosis of Crohn’s being based mainly on marked rectal sparing, suggesting a possible ischaemic aetiology. It would be very interesting to know whether the cohorts described by Khalili et al also showed a predominance of isolated colonic Crohn’s disease among those taking oral contraceptives