Design Prospective multicentre observational study. Objective To evaluate details and effects of homeopathic treatment in patients with psoriasis in usual medical care. Methods Primary care patients were evaluated over 2 years using standardized questionnaires, recording diagnoses and complaints severity, health-related quality of life (QoL), medical history, consultations, all treatments, and use of other health services. Results Forty-five physicians treated 82 adults, 51.2% women, aged 41.6 +/- 12.2 (mean +/- SD) years. Patients had psoriasis for 14.7 +/- 11.9 years; 96.3% had been treated before. Initial case taking took 127 +/- 47 min. The 7.4 +/- 7.4 subsequent consultations (duration: 19.4 +/- 10.5 min) cumulated to 169.0 +/- 138.8 min. Patients received 6.0 +/- 4.9 homeopathic prescriptions. Diagnoses and complaints severity improved markedly with large effect sizes (Cohen's d= 1.02-2.09). In addition, QoL improved (SF-36 physical component score d = 0.26, mental component score d = 0.49), while conventional treatment and health service use were considerably reduced. Conclusions Under classical homeopathic treatment, patients with psoriasis improved in symptoms and QoL.