Effectiveness and side-effects of the new topical halogenfree corticosteroid methylprednisolone aceponate (MPA) (0.1% in commercial o/w or w/o emulsions) were tested in six multicentre controlled double-blind studies, using betamethasone valerate (BMV) as control (0.1% in o/w emulsion); a total of 1723 patients with various kinds of eczema were included into these studies. Treatment was carried out for a maximum of 3 weeks; the choice of vehicle (w/o or o/w emulsion) was left for the attending physicians to decide. In addition, effectiveness of 1×/day application of MPA as compared to 2×/day and to 2×/day of BMV was investigated. The following conclusions can be drawn from these studies:1. All regimens tested proved approximately equally effective, more than 90% of the patients being symptom-free or greatly improved after 3 weeks.2. MPA in cream and ointment performed equally well.3. 1×/day application of MPA was equally effective as 2×/day MPA and 2×/day BMV.4. Tolerability was excellent; systemic side-effects were not observed; mild to moderate local complaints were reported in 5% of patients in all groups.