The effectiveness of commercially available, chemically generated, topical exothermic pads that elevate skin surface temperature from 42 to 43 degrees C was stressed in 22 patients with psoriasis. Control sites were treated with conventional modalities such as Goeckerman's regimen, as well as with occlusion with nonexothermic pads. Skin lesions in 19 patients disappeared after the use of hyperthermia. The average time required for complete regression in the treated areas was 27 days with hyperthermia, compared with 44 days with Goeckerman's regimen. There were no hyperthermic side effects. Seventeen patients whose skin lesions disappeared with the use of both hyperthermia and Goeckerman's regimen were subsequently reexamined. The hyperthermia produced an equal or longer duration of remission than did Goeckerman's regimen.