The aim of this study was to evaluate the sensitivity of two patient-centred outcome measures to the topical application of a corticosteroid (betamethasone) in the treatment of oral lichen planus (OLP). Forty-eight patients with clinical and histological features of OLP were recruited to take part in a 6-week study of the effectiveness of topical betamethasone for the treatment of symptomatic OLP. Participants completed a questionnaire incorporating the 16-item UK Oral Health Related Quality Of Life measure (OHQOL) and the 14-item Oral Health Impact Profile (OHIP-14), rated their pain on 'global' and visual analogue scales (VAS) and underwent an oral examination, at the start and end of the trial. Four (8\%) patients failed to complete the study. The clinical signs of OLP had improved for half (22) of the patients following treatment. Twenty-nine (66%) reported that their oral pain had reduced ('global' scale). More objectively, there were significant differences in VAS ratings of pain (P =0.005), OHIP-14 scores (P =0.036) and OHQOL scores (P =0.003) between the start and end of the trial. In conclusion, both OHQOL and OHIP-14, patient-centred outcome measures are sensitive to the clinical effects of topical betamethasone in the treatment of oral lichen planus.