Oral Lichen Planus(OLP) is a idiopathic chronic inflammatory disease with more difficult to clear and higher recurrent rate than cutaneous lesions. But, there has been no estabilished theories about the proper treatment for OLP. The purpose of this study is to examine the clinical feature, relationship with systemic disease and dental treatment of OLP patients of Korea and to gain helpful information about clinical characteristics and treatment of OLP. The subjects chosen for the study were 54 patients who had visited Department of Oral Diagnosis & Oral Medicine at Yonsei University Dental Hospital Dental Hospital and diagnosed as OLP. Previous clinical records has been reviewed and questionnaires, oral examination, laboratory examination were done and recorded. The following results were obtained : 1. Of the 54 patients, 21 were men and 33 were women with an average age of 47.8 years. 2. The most common intraoral site was bilateral buccal mucosa, followed by unilateral buccal mucosa, gingiva, vesibule, lip mucosa, glossal mucosa, palatal mucosa and mouth floor. 3. The mixed, erosive and reticular form of OLP was most frequent(83.3%) clinical form. 4. OLP patients with liver disease were 5, and drug medication patients were 7. But, we could not find its evidence of association with OLP. 5. Associated events on onset of symptom were stress, denture wearing, dental treatemtn, and common cold. 6. Associated symptoms were dry mouth, tingling, sore throat, and altered taste perception. 30.8% of patients had no specific associated symptoms. 7. Aggravating factors of symptom were peppery food, hot food, fatigue, toothpaste, salty food, sour food, tension, and conversation. Reducing factors were cold food, sleeping. 69.2% of patients had no specific reducing factors. 8. There were no significant differences between normal papulation and OLP patients in CBC, SGOT< SGPT, Serum iron, Total iron binding capacity. 66.7% of subjects were positive response to fungus study for Candida Albicans. The incidence of stress and dental treatment on onset of symptom appeared high in OLP patients. Especially, high incidence of positive response to fungus study for Candida albicans, prescription of anti-fungal agents and dental treatment considerations may be helpful to treatment of OLP.