Efficacy and Safety of Topical Essential Oil Extracted From Zingiber Cassumunar Rokb in Osteoarthritis

Inclusion Criteria: * Diagnosis: osteoarthritis of the knee at least on side with standard radiologic method within 6 weeks (Kellgren-Lawrence radiographic grading scale at least 1) * Pain visual analog scale at rest at least 40 mm * No previous analgesic treatment or receiving stable dose of analgesic drugs at least 2 weeks. If previously treated with antidepressants, glucosamine, chondroitin or diacerein, dosage should be stable for at least 3 months. * Agree to attain non-pharmacologic treatment as prior to participate the study Exclusion Criteria: * having an open wound or abnormal skin at site of application * having diagnose with other chronic arthritis such as rheumatoid arthritis * history of allergy to the extraction of Zingiber cassumunar Roxb * pregnancy or breastfeeding