The following treatments for psoriasis are compared with each other: PUVA, UVB, retinoid 10-9359 alone and in combination with 4 mg triamcinolone or UVB. The best results were obtained with UVB alone and with the combination of UVB and retinoid. Based on a survey of various psoriasis therapies during the last 40 years, it is concluded that a final assessment of the value of a new therapy is only possible after some time.