Thirty-three patients with the depigmentation disorder vitiligo were successfully treated with a new topical application of pseudocatalase, calcium and short-term UVB light exposure. First repigmentation occurred in the majority of cases after 2-4 months. Complete repigmentation on the face and dorsum of the hands appeared in 90% of the group. In all patients, active depigmentation was arrested. None of them developed new lesions during treatment. No recurrence of the disease was observed during a 2-year follow-up. The rationale for this pilot study originated from a recent understanding of vitiligo at the molecular level. The involved epidermis produces hydrogen peroxide due to defective tetrahydrobiopterin recycling and increased monoamine oxidase A activity, whereupon catalase is inactivated. In addition, calcium homeostasis is perturbed in the affected skin. The substitution for insufficient catalase by a pseudocatalase together with calcium and UVB exposure lead to effective repigmentation.