The treatment of osteoarthritis, a disease that eventually affects the majority of the older population, involves the alleviation of symptoms such as pain and stiffness, and the reduction of inflammation. The double-blind, placebo-controlled, crossover study reported here examined the effect of Hyben Vital, a herbal remedy made from a subtype of Rosa canina and recently reported to have anti-inflammatory properties, on the symptoms of osteoarthritis. One hundred and twelve patients with osteoarthritis were randomly allocated to treatment with either Hyben Vital 5 g daily or an identical placebo for 3 months, followed immediately by the alternative treatment. The patients assessed changes in joint pain and stiffness after each treatment period on a 5-point categorical scale. General wellbeing, including mood, sleep quality and energy were also assessed and recorded in a personal diary. The results in the two arms of the crossover differed markedly. Group A (placebo first) showed significantly more improvement from Hyben Vital than from placebo, p < 0.0078 for pain and < 0.0025 for stiffness. But Group B (Hyben Vital first) revealed a positive effect of the same order as for Hyben Vital in group A, not only from the active drug, but also from placebo (difference not significant). An identical pattern was observed when we evaluated general wellbeing from the diary records. When patients, on the basis of reduction in joint pain, were divided into responders and non-responders, the first 3 months of active treatment (group A) showed a response rate of 31/47 (66%) compared to that of placebo (group B) 18/50 (36%), p < 0.0185. No major side effects occurred in either group. The data indicate that Hyben Vital reduces the symptoms of osteoarthritis. We interpret the marked differences in the responses of the two groups as indicating a strong "carryover" effect of Hyben Vital.