BACKGROUND AND AIM: The effect of vitamin D supplementation on immune disorders has been a topical research focus. The aim of this systematic review was to examine the current evidence of the effect of vitamin D supplementation as a therapy for colitis. METHODS: The following databases were searched: MEDLINE, Pubmed, Scopus, Web of Knowledge, Cinicaltrials.gov and the Cochrane Central Register of Controlled Trials using the terms 'inflammatory bowel disease' 'Crohn's disease' 'ulcerative colitis' 'colitis' [and] 'vitamin D'. Both human and animal studies published in English language were examined. The reference lists of included studies and review articles were manually searched for any relevant studies. RESULTS: Four studies were included in this systematic review. All reported an improvement in disease activity with vitamin D supplementation. The only high quality human study reported a non-significant reduction of relapse rate for Crohn's disease. No major adverse effects of vitamin D supplementation were reported. CONCLUSIONS: Although there is some evidence that supplemental vitamin D, as an adjunctive treatment, may help in controlling colitis, this evidence is not enough to justify using vitamin D in treating inflammatory bowel disease (IBD). Large high quality placebo-controlled randomised controlled trials are needed to explore a possible benefit of using vitamin D in treating IBD.