This study was performed to assess the effectiveness and short-term and long-term safety of oral khellin plus UVA (KUVA) in patients with vitiligo. Twenty-eight patients (13 males and 15 females; mean age, 34 years; [age range, 15-51 years]) most with extensive generalized vitiligo of more than 6 months duration had received KUVA at sometime during a 14-year period. The response to treatment (i.e. repigmentation of depigmented areas) was rated retrospectively comparing photographs taken before and after therapy and correlation analysis revealed that it was statistically significantly linked to the number of KUVA treatments (r = 0.833, P = 0.001) and to total cumulative UVA dose (r = 0.840, P = 0.001). Of 17 patients who had continued therapy for longer than 3 months, 7 (41%) had a good response (i.e., more than 70% repigmentation of lesional skin) after a mean of 194 treatments (range, 69-386 treatments) and a mean cumulative UVA dose of 2,036 J/cm2 (range, 690-4,411 J/cm2), whereas lower response grades were observed in the patients with lower treatment numbers. The most common short-term side effect was mild nausea, occurring in 8 of 28 patients (29%), and mainly in the first week(s) of treatment. Follow-up assessment at a mean of 40 months (range, 4-110 months) after the end of KUVA therapy available in 23 of 28 patients revealed no skin cancers or actinic skin damage in any patient. These data indicate that KUVA seems to be safe as well as effective for vitiligo, provided treatment is administered long enough.