Abstract: Vitamin A Acid film,a production of the Beijing Sixth Pharmaceutical Manufactory,was used to treat 24 cases of lichen planus.The curative effect was excellent.In 2 cases,the white keratinized striae disappeared and no hyperemia of the basilar membrane was observed.No complain of irritating and spontaneous pain and no recurrence of the disease were observed within 3 months.In 21 cases,the white keratinized striae disappeared partially,the basilar membrane was basically normal and there was no spontaneous and irritating pain.Only 1 case showed that the white keratinized striae disappeared partially.The hyperemia ofbasilar membrane or spontaneous pain still existed,and even erosion of the oral mucosa could be seen. Topical application of Vitamin A acid film in the treatment of hyperkeratosis of the oral mucosa has many advantages,such as less irritation effect,easy to operate and it can be plastered on the lesion for a considerable gong time.