Efficacy and safety of topical Matricaria chamomilla L. (chamomile) oil for knee osteoarthritis: A randomized controlled clinical trial

•We assessed the efficacy and safety of chamomile oil in knee osteoarthritis.•We evaluated the patients in the terms of analgesic use, function and stiffness.•Chamomile oil significantly reduced the patients' need for acetaminophen use.•It may show some beneficial effects on function and stiffness of the patients.•The patients did not report any local or systemic adverse events by using it.

ObjectiveTo assess the efficacy and safety of topical Matricaria chamomilla (Chamomile) oil in patients with knee osteoarthritis.MethodPatients were randomized and treated with topical chamomile oil, diclofenac or placebo, 3 times/day for 3 weeks. They were allowed to use acetaminophen as analgesic. The patients were asked about their total acetaminophen use. Moreover, they were assessed in the terms of pain, physical function and stiffness by using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at the enrolling and weekly.ResultsChamomile oil significantly reduced the patients' need for acetaminophen (P = 0.001) compared with diclofenac and placebo. However, there were no significant differences in WOMAC questionnaire domains. The patients did not report any adverse events by using chamomile oil.ConclusionChamomile oil decreased the analgesic demand of patients with knee osteoarthritis. In addition, it may show some beneficial effects on physical function, and stiffness of the patients.