Siddha Medicine is a complete holistic medical system which has been prevalent in the ancient Tamil land, and is the foremost of all other medical systems in the world. Its origin goes back to B.C 10,000 to B.C 4,000. Siddha system of medicine is divine in origin. It is believed to have been passed on by the 'Siddhars', incarnations of Lord Shiva, to serve humanity. According to the Siddha system, the individual is a microcosm of the universe, the whole universe is Macrocosm, what exists in macrocosm exists in microcosm too. Cosmic energy is the highest form of life force that is omnipresent, omnipotent, and omniscient- it exists in the cosmos, between the galaxies, and in the space. It is this energy that animates life and maintains balance in the entire universe. Cosmic energy exists within us , in the same way Siddhars have found through their higher intellectual powers that herbs, plants, trees do have cosmic energy for example in some herbs the cosmic energy will be in stem, in some it will be in root or in bark or in leaves or in stem. When we consume those herbs that’s how it cures our mind, body and soul integeratively. 

Siddha System of medicine developed for spiritual enlightenment. ‘Siddhars’ were evolved spiritual beings who went beyond enlightenment to accomplish the final yoga of attaining the ultimate perfection as becoming one with God. The clarified intellect and heightened intuition of Siddhars resulting from their yogic powers, enable them to see beyond human level, as Sage Thirumoolar in Thiruanthiram  has written about 72,000 naadis, Siddhars vividly written about human anatomy, physiology, diseases, diagnostic methods, medicinal uses of plants and about everything for the welfare of the human kind. The System is said to have emerged in antiquity, from the highly evolved consciousness of the Siddhars. 

Palm leaf manuscripts say that the Siddha system was first described by Lord Shiva to his wife Parvati. Parvati explained all this knowledge to her son Lord Muruga.  He taught all these knowledge to his disciple Sage Agasthiyar.   Sage Agasthiyar taught 18 Siddhars and they spread this knowledge to human beings. According to the Siddha medicine, the treatment is aimed at restoring balance to the mind-body-spirit system. It lays equal emphasis on the body, mind and spirit and strives to restore complete harmony to the various psychological and physiological functions of the body. Siddha system of medicine places more importance on preventing diseases than curing.

Siddha focused to "Ashtamahasiddhi," the eight supernatural powers. Those who attained or achieved the above said powers are known as Siddhars. There were 18 important Siddhars in olden days and they developed this system of medicine. Hence, it is called Siddha medicine of these 18 Siddhars, Sage Agasthiyar is believed to be the father of Siddha medicine. The Siddhars wrote their knowledge in palm leaf manuscripts, fragments of which were found in parts of South India. There is a huge collection of Siddha manuscripts kept by traditional Siddha families.

Siddhars were of the concept that a healthy Soul can only be developed through a healthy body. So they developed methods and medication that are believed to strengthen their physical body and thereby their souls. Men and women who dedicated their lives into developing the system were called Siddhars. They practiced intense yogic practices, including years of periodic fasting and meditation, and were believed to have achieved supernatural powers and gained the supreme wisdom and overall immortality. Through this spiritually attained supreme knowledge, they wrote scriptures on all aspects of life, from arts to science and truth of life to miracle cure for diseases.

From the manuscripts, the Siddha system of medicine developed into part of Indian medical science. Today there are recognized siddha medical colleges, run under the government universities, where Siddha medicine is taught.

— Sri Sakthi Amma