A patient with generalized lichen planus with lesions in the infrequent localization like face, palms, soles and an extensive erosion of glans penis, is described in a 46 year old patient. He had received various treatment which include systemic steroids, without improvement. After treatment with thalidomide (initial doses 300 mg/day for 2 weeks and 200 mg/day for further 10 weeks) he presents resolution of his lesions and symptomatology. A review of lichen planus etiopathogenesis, making emphasis in the immunological hypothesis is made. As well as the different uses and action mechanism of thalidomide in various inflammatory dermatoses.