Fifty two psoriatic patients were treated with a new experimental fluorescent lamp (Philips TL-01) emitting a narrow band at 311 +/- 2 nm (UVB) which had the advantage of a reduction in burning and carcinogenic wavelengths when compared with conventional broad band UVB therapy. Results of the '311' treated group when compared with broad band UVB therapy revealed a similar percentage of patients achieving a satisfactory response with fewer burning episodes and an increase in duration of remission.