That vitamin A has a marked antikeratinizing effect has been established experimentally in animals and in humans.1 It has also been shown that this effect may be produced by topical application.2,3 In view of reports suggesting a favorable action of vitamin A given by injection in vulvar leukoplakia4 and senile keratoses,5 a clinical trial of this compound in topical form seemed indicated. Ten patients with typical oral leukoplakia of from 3 months' to 10 years' duration, ranging in severity from Grades II to IV of Thoma,6 were treated with oral troches containing 150,000 units of vitamin A each.* The patients were instructed to remove their dentures and allow one troche to dissolve slowly in the mouth twice or three times daily. Treatment periods varied from two to six months. All patients were examined every four to six weeks, and photographs were taken for the record.