Background and aims: The causes of relapses of ulcerative colitis (UC) are unk nown. Dietary factors have been implicated in the pathogenesis of UC. The aim of this study was to determine which dietary factors are associated with an increa sed risk of relapse of UC. Methods: A prospective cohort study was performed wit h UC patients in remission, recruited from two district general hospitals, who w ere followed for one year to determine the effect of habitual diet on relapse. R elapse was defined using a validated disease activity index. Nutrient intake was assessed using a food frequency questionnaire and categorised into tertiles. Ad justed odds ratios for relapse were determined using multivariate logistic regre ssion, controlling for non-dietary factors. Results: A total of 191 patients we re recruited and 96%completed the study. Fifty two per cent of patients relapse d. Consumption of meat (odds ratio (OR) 3.2 (95%confidence intervals (CI) 1.3- 7.8)), particularly red and processed meat (OR 5.19 (95%CI 2.1-12.9)), protein (OR 3.00 (95%CI 1.25-7.19)), and alcohol (OR 2.71 (95%CI 1.1-6.67)-) in th e top tertile of intake increased the likelihood of relapse compared with the bo ttom tertile of intake. High sulphur (OR 2.76 (95%CI 1.19-6.4)) or sulphate (OR 2.6 (95%CI 1.08.-6.3)) intakes were also associa ted with relapse and may offer an explanation for the observed increased likelih ood of relapse. Conclusions: Potentially modifiable dietary factors, such as a h igh meat or alcoholic beverage intake, have been identified that are associated with an increased likelihood of relapse for UC patients. Further studies are nee ded to determine if it is the sulphur compounds within these foods that mediates the likelihood of relapse and if reducing their intake would reduce relapse fre quency. Background and aims: The causes of relapses of ulcerative colitis (UC) are unk nown. Dietary factors have been implicated in the pathogenesis of UC. The aim of this study was to determine which dietary factors are associated with an increa sed risk of relapse of UC. Methods: A prospective cohort study was performed wit h UC patients in remission, recruited from two district general hospitals, who w ere followed for one year to determine the effect of habitual diet on relapse. R elapse was defined using a validated disease activity index. Nutrient intake was assessed using a food frequency questionnaire and categorized into tertiles. Ad justed odds ratios for relapse were determined using multivariate logistic regre ssion, controlling for non-dietary factors. Results: A total of 191 patients we re recruited and 96% completed the study. Fifty two per cent of patients relapse d. Consumption of meat (odds ratio (OR) 3.2 (95% confidence intervals (CI) 1.3-7.8)), particularly red and processe (OR 5.19 (95% CI 2.1-12.9)), protein (OR 3.00 (95% CI 1.25-7.19)) and alcohol intake increased the likelihood of relapse compared with the bo ttom tertile of intake. High sulphur (OR 2.76 (95% CI 1.19-6.4)) or sulphate (OR 2.6 (95% CI 1.08.- 6.3)) intakes were also associated with ted with relapse and may offer an explanation for the increased likelihood of cancers of relapse. Conclusions: Potentially modifiable dietary factors, such as ahigh meat or alcoholic beverage intake, have been identified that are associated with an increased likelihood of relapse for UC patients. are nee ded to determine if it is the sulphur compounds within these foods that mediates the likelihood of relapse and if reducing their ramming would reduce relapse fre quency.