Lichen planus (LP) is a common chronic inflammatory mucocutaneous disease with an immunologic etiology ,which has number of different clinical forms. Alternative natural or herbal origine drugs with antioxidant and anti-inflammatory properties have been used individually or in combination with systemic corticosteroids in order to decrease adverse drug reactions.

This study was conducted to evaluate the effect of quercetin on treatment of erosive -atrophic lesions of oral lichen planus (OLP).

Inclusion Criteria:

• confirmation of clinical diagnosis of Atrophic and erosive lichen planus by histological examination
• two weeks wash out periods after the last treatment
• having the experience of atrophic and erosive lesion greater than 1 cm having the experience of pain and burning greater than 3.5 in VAS Score

Exclusion Criteria:

• confirmation of dysplasia and malignancy in histologic examination
• confirmation of lichenoid reaction in histologic examination
• pregnancy and breast feeding
• using fluorokinolon and cyclosporin which interact with quercetin