Siddha system of medicine is practiced mostly in South India. This system of medicine maintains a distinctive identity of its own but has a close affinity to Ayurveda. This system is considered to be of pre-Vedic period; it is identified with the Dravidian culture and is closely attached with the Tamil civilization. The term “Siddha” has come from Siddhi, which means achievement. Siddhars were the persons who achieved supreme knowledge in the field of medicine, through the practice of bhakti, yoga, or tapas (meditation). As the years passed, this system of medicine interacted with the other streams of medicines and developed as a separate stream of medicine. The materia medica of Siddha system of medicine depends to a large extent on the drugs of metal and mineral origin, in contrast to Ayurveda of earlier period, which was mainly dependent upon drugs of vegetable origin.