Objective: An evaluation of the efficacy of the combination of ginger (Zingiber officinale) and plai (Zingiber cassumunar) gel for the treatment of osteoarthritis of the knee using 1% diclofenac gel as a comparator.
Material and Method: A double-blind, randomized, controlled trial of the combination of 4% ginger and plai extract in a gel (Plygersic gel) as compared with a 1% solution of diclofenac in patients with osteoarthritis knees. The number of participants in each group totaled fifty. The length of treatment was a 6 week period. The efficacy of the drugs was monitored by using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The t-test was used to compare the scores before and after treatments in each group. The repeated ANOVA was used to compare the scores between the two groups.
Results: Both Plygersic gel and diclofenac gel could significantly improve knee joint pain, symptoms, daily activities, sports activities and quality of life measured by KOOS following 6 weeks of treatment. In the repeated ANOVA, there were no differences in the results between the Plygersic and diclofenac gel groups.
Conclusion: Plygersic gel relieves joint pain and improves problematic symptoms and improves the quality of life in osteoarthritis knees during a 6 week treatment regimen with no differences to the 1% Diclofenac gel group.

Keywords: Ginger, Zingiber officinale, Plai, Phlai, Zingiber cassumunar, Topical gel, Osteoarthritis