["There have been no previous reports assessing the effectiveness of azathioprine (AZA) in the treatment of orofacial granulomatosis (OFG). This report is a review of patients receiving AZA for active OFG with or without concomitant gut Crohn's disease (CD) in a specialist tertiary referral centre.", 'Clinical response was defined by Global Physician Assessment at 4-, 12- and 24-month follow-up and a standardised oral disease activity score (ODAS).', 'Sixty of 215 patients seen with OFG in our clinic over a 12-year period were treated with AZA. Of these, 22 had concomitant CD. The proportion of patients responding to AZA with a diagnosis of CD/OFG vs. OFG only at 4, 12 and 24 months were 54% vs. 21% (P = 0.03), 59% vs. 21% (P = 0.003) and 41% vs. 24% (P = 0.16), respectively. A statistically significant difference was seen between starting and follow-up ODAS scores at 4 months in the CD/OFG group which was not observed in the OFG only group. Factors predicting a need for AZA included a diagnosis of intestinal CD, sulcal swelling, sulcal ulcers and upper lip involvement. The factor predicting response to treatment was a diagnosis of CD at 12 months of follow-up. No difference in the number of adverse effects was observed between the two groups of patients.'] Is azathioprine effective for oral involvement in Crohn 's disease but not for orofacial granulomatosis alone?