P54FP is an extract of Indian and Javanese turmeric, Curcuma domestica and Curcuma xanthorrhiza respectively, which contains a mixture of active ingredients including curcuminoids and essential oils. A randomised, double-blind, placebo-controlled, parallel group clinical trial of P54FP as a treatment for osteoarthritis of the canine elbow or hip was conducted to assess its efficacy and safety. Sixty-one client-owned dogs with osteoarthritis were recruited through first-opinion practices and examined at a single centre. After a two-week wash-out period, they were randomly allocated to receive P54FP or a placebo orally twice daily for eight weeks, and were re-examined after four, six and eight weeks of treatment. The effectiveness of the treatment was assessed in terms of the peak vertical force (PVz) and vertical impulse of the affected limbs, as measured with a force platform, by clinical assessments of lameness and joint pain by the investigators, and overall assessments of the response to treatment by the investigators and the owners. The results from 25 P54FP-treated dogs and 29 placebo-treated dogs showed that there was no statistically significant difference between the groups in terms of the Pvz of the affected limb. The investigators' overall assessment showed a statistically significant treatment effect in favour of P54FP (P=0.012), but the owners' assessment just failed to reach statistical significance (P=0.063). No serious adverse effects were recorded, but two P54FP-treated dogs and four placebo-treated dogs were withdrawn from the study because their condition deteriorated.