A randomized double-blind active-controlled clinical trial on the efficacy of topical basil (Ocimum basilicum) oil in knee osteoarthritis

Randomized, double-blind, active-controlled clinical trial in adults with knee osteoarthritis treated at an orthopedic clinic in Fasa, Iran. For the basil oil group, 50 participants were randomized and 43 completed; the diclofenac gel group also had 50 randomized and 43 completed.

Topical basil oil (Ocimum basilicum) formulated with sesame oil was applied to the knee at 1.5 cc three times daily for 4 weeks. The comparator was topical diclofenac sodium 1% gel, one fingertip unit, applied with the same frequency and duration.

Topical basil oil improved knee osteoarthritis symptoms, but it did not differ significantly from diclofenac gel on the measured outcomes. In the basil oil group, VAS pain decreased from 61.05 ± 9.67 at baseline to 51.28 ± 10.12 at 2 weeks and 44.07 ± 11.87 at 4 weeks. Between-group comparisons showed no significant differences at 2 weeks (p = 0.619) or 4 weeks (p = 0.880), and other outcomes were also not different, including knee flexion angle, 8-m walking test, analgesic use, WOMAC pain, physical function, knee stiffness, and total WOMAC scores. The authors concluded that topical basil oil was well tolerated and produced symptom and function improvements similar to diclofenac gel.

The trial was small and single-center, with only 43 participants per active arm completing follow-up. Treatment duration was short at 4 weeks, limiting assessment of sustained efficacy and safety. The active-controlled design without a placebo arm makes it harder to separate treatment effects from nonspecific improvement over time.