Oral lichen planus is a common autoimmune chronic inflammatory disease which affects about 2 per cent of adults. The reticular form shows bilateral, white, asymptomatic striations (Wickham's striae) or papules, mostly located on the buccal mucosa. The erosive form appears as painful ulcers with white borders (radiating striae). If the erythema and ulcers are generalized, it is called desquamative gingivitis. In asymptomatic patients, no treatment is required. Otherwise topical corticosteroid gels may be indicated. Periodic follow-up are recommended because the condition is assumed to be associated with an increased risk of malignancy.