The use of topical preparations for symptom relief is common in osteoarthritis. The effects of ibuprofen (5%) and arnica (50 g tincture/100 g, DER 1:20), as gel preparations in patients with radiologically confirmed and symptomatically active osteoarthritis of interphalangeal joints of hands, were evaluated in a randomised, double-blind study in 204 patients, to ascertain differences in pain relief and hand function after 21 days' treatment. Diagnosis was according to established criteria; primary endpoints were pain intensity and hand function; statistical design was as per current regulatory guidelines for testing topical preparations. There were no differences between the two groups in pain and hand function improvements, or in any secondary end points evaluated. Adverse events were reported by six patients (6.1%) on ibuprofen and by five patients (4.8%) on arnica. Our results confirm that this preparation of arnica is not inferior to ibuprofen when treating osteoarthritis of hands.