Background: Siddha system of medicine is the most primitive medical system. This system has a vast range of external therapies for health management. Most of these therapies aim in maintaining a healthy equilibrium of the vital humors (Vali, Azhal, Iyam).There are 32 types of pura maruthuvam in siddha system. Ottradam is one among them. It is a warm application to a part of the body. Azhal keel vayu is one type of Vatha disease, which is characterized by pain, swelling and restricted movements in the knee joints. The signs and symptoms of osteo arthritis(OA) can be correlated with Azhal keel vayu.

Objective: The aim of this study to evaluate the effectiveness of ottradam therapy on Azhal keel vayu.

Material and Methods: 10 patients withsymptoms of OA were admitted in In Patient Department RVS Siddha Medical college and Hospital. Notchi leaves (Vitex negundo) was used for ottradam procedure. Ottradam was given in morning, for 7-15 days and the patients were monitored clinically.

Results and Conclusion: Pain was measured by using Universal Pain Assessment Scale. Pain, Swelling, Restriction of movements in the knee joint got reduced in the patients at the end of the therapy. This study reveals that ottradam therapy is effective in reducing the symptoms of Osteo arthritis.