Forty patients with relapsing plaque psoriasis involving more than 20% body surface were treated either with cyclosporin A (CyA) plus PUVA or the retinoid etretinate plus PUVA (RePUVA). They initially received either CyA (2 weeks) or etretinate (1 week) alone and then PUVA was given concomitantly until complete remission. The patients were monitored over a period of 6 months and any relapse recorded. With each combined treatment regimen, CyA plus PUVA and RePUVA, the patients cleared within comparable periods of time (mean treatment period of 5.3 vs. 4.7 weeks after initiation of therapy and 3.3 vs. 3.7 weeks after initiation of PUVA). However, the cumulative UVA dose required for clearance (110.9 J/cm2 vs. 62.1 J/cm2 (P less than 0.05)) and the incidence of severe and early relapses were significantly higher in the CyA cohort. Within 6 months severe relapses had occurred in 58% of CyA plus PUVA but only in 15% of RePUVA-treated patients (P less than 0.001). This suggests that the CyA plus PUVA regimen as performed in this study is less effective than RePUVA.