Objective: To study the effects of UV-B therapy and saline spa water given alone or in combination for the treatment of psoriasis. Design: Randomized, controlled, comparative study with blinded observers. Setting: Salies de Bearn, saline spa water center located in the southwest of France. Participants: Seventy-one adult patients with psoriasis with a Psoriasis Area and Severity Index (PASI) score greater than 10. Intervention: Patients were randomly assigned to I of 3 treatments: spa water alone (group A); UV-B 311-nm phototherapy alone (group B); and a combination of the 2 therapies (group C). The 3 groups were treated on a daily basis 5 days a week for a total of 21 days. Main Outcome Measures: Change in PASI score from baseline as determined by an investigator blinded to randomization; variation in quality of life, adverse effects, and long-term effects (1 year after treatment). Results: Four patients dropped out because of secondary effects. Efficacy was similar in groups B and C, with changes in PASI of -64% and -55%, respectively at 3 weeks. For group A, change in PASI was -29%, thus showing a minor therapeutic effect of saline spa water alone and poor efficacy compared with groups B and C (P<.001), More adverse effects were reported in groups A and C but did not reach significance. Combined saline spa water and UV-B therapy had no sparing effect on UV-B dosages. One year after treatment, no longterm benefit could be attributed specifically to a given regimen, but the patients had overall significantly better PASI scores than at baseline. Conclusions: Saline spa water alone had a minor therapeutic effect in psoriasis, and the beneficial effect of bathing to enhance phototherapy was not demonstrated.