Background: Liver enzymes appear to be involved in oral lichen planus (OLP), but it is not known whether the elevation develops concomitantly with exacerbations of disease. We compared the levels of serum hepatic aspartate (AST) and alanine (ALT) aminotransferases as markers of OLP exacerbation in patients with chronic hepatitis C from those with chronic liver disorders, seronegative for hepatitis C virus (HCV)., Methods: We studied 71 patients with OLP, (48 HCV seropositive and 23 HCV seronegative with chronic liver diseases) measuring AST and ALT. Association of HCV infection status with serum aminotransferase levels in relation to several types of OLP, exacerbations, and clinical score was studied by means of logistic and linear regression (correcting for age and sex)., Results: Of 476 patients screened, 71 were eligible for the study. Patients in the HCV seropositive group had more elevation of AST and ALT levels (mean level, 51.0 U/l; normal level, <45) than patients in the HCV seronegative group (mean level, 47.5 U/l). Mean serum AST and ALT exceeded the upper limit of the normal range in 33 of 48 (68.8%) in the HCV antibody-positive group and in 9 of 23 (39.5%) in the HCV antibody-negative group. Exacerbations of OLP were more frequent in the high-level AST and ALT group, while HCV status group played a minor role., Conclusions: Among patients with OLP, mild elevation in aminotransferase levels was more common in patients infected with HCV. AST and ALT concentrations were elevated in association with exacerbation of OLP., (© 2017 The International Society of Dermatology.)