Siddha Medicine (Tamil Citta or Tamil maruttuvam) is a system of traditional medicine originating in ancient Tamilakam in South India. Traditionally, it is taught that the siddhars laid the foundation for this system of medication. Siddhars were spiritual adepts who possessed the ashta siddhis, or the eight supernatural powers. The Siddha System of Medicine (Traditional Tamil System of medicine), which has been prevalent in the ancient Tamil land, 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. As per the textual and archeological evidences which indicate the remote antiquity of the Dravidian civilization of the erstwhile submerged land Kumarikandam, that is the Lemuria continent situated in the Indian ocean, the Siddha System of Medicine is contemporaneous with those of the submerged lands Egyptian, Mesopotamian, Chinese and Grecian medicines. The uniqueness of Siddha System is evident by its continuous service to the humanity for more than 5000 years in combating diseases and also in maintaining its physical, mental and moral health while many of its contemporaries had become extinct long ago. Agastya is considered the first siddha and the guru of all siddhars; the siddha system is believed to have been handed over to him by Murugan, son of Shiva and Parvati.

The roots of the ancient Siddha System are intertwined with the mythology and culture of the ancient Tamil civilization that existed in the southernmost tip of the Indian peninsula, predating much of recorded history. Mythically, the origin of Siddha is attributed to Lord Siva, who is supposed to have handed it down to his consort Parvathi (Shakthi), who in turn passed on the sacred knowledge to Nandi, from whom it was transmitted to the first of "Siddhars". Siddha is a Tamil word derived from "siddhi" -- attaining perfection in life or heavenly bliss. The Siddha science is a traditional treatment system generated from Dravidian culture. 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 Agasthya. Agasthya taught 18 Siddhars and they spread this knowledge to human beings.

Siddha focused to "Ashtamahasiddhi," the eight supernatural power. 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. The Siddhars wrote their knowledge in palm leaf manuscripts, fragments of which were found in parts of South India. It is believed that some families may possess more fragments but keep them solely for their own use. There is a huge collection of Siddha manuscripts kept by traditional Siddha families.

The contributors of Siddha system, the Siddhars, of Tamil land, were mystics, yogis, poets, devotees, seers and medical men of various combinations and various statures. They were super human beings who possessed supernatural powers (like Eight types of Siddhis). They were the greatest scientists of ancient times and were the guardians of the world and they existed, and still exist, for the benefit of the public at large. They were men of great practical knowledge and wisdom. They had full awareness of the nature and activities of all the objects in this planet and of all times-past, present and future. They were mainly responsible for the growth and development not only of Tamil medicine that includes alchemy, medicine, yoga, kayakalpa (rejuvenation therapy), philosophy, astronomy, astrology, varma, muppu, thokkanam etc., but also for many other sciences of public utility.

According to the manikandan, there were 22 principal siddhars. Of these 22, Agasthya is believed to be the father of siddha medicine. 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. Most of the practicing Siddha medical practitioners are traditionally trained, usually in families and by gurus (teachers). When the guru is a martial arts teacher, he is also known as an ashan. They make a diagnosis after a patient's visit and set about to refer to their manuscripts for the appropriate remedies, which a true blue physician compounds by himself or herself, from thousands of herbal and herbo-mineral resources. The methodology of siddha thought has helped decipher many causes of disorders and the formulation of curious remedies which may sometimes have more than 250 ingredients.

According to the Siddha system, the individual is a microcosm of the universe. The human body consists of the five primordial elements-earth, water, fire, air and space, the three humours-vatha, pitta and kapha and seven physical constituents. Food is the basic building material of the human body and gets processed into humours, tissues and wastes. The equilibrium of humours is considered as health and its disturbance or imbalance leads to a diseased state. Reflecting this theory of cosmic oneness, the five senses are said to correspond with the five elements. Ether (Veli) is responsible for hearing; air (katru) for sense of touch; fire (thee) for sight; water (neer) for taste; and earth (mann) for the sense of smell. Siddha is a comprehensive system that places equal emphasis on the body, mind and spirit and strives to restore the innate harmony of the individual. Treatment is aimed at restoring balance to the mind-body system. Diet and lifestyle play a major role not only in maintaining health but also in curing diseases. This concept of the Siddha medicine is termed as pathiam and apathiam, which is essentially a list of do's and don'ts.

Varmam are vital points in the body that act as energy transformers or batteries. They form centres for boosting the vital life-force Uyir Sakthi flow through the intricate nadi system of the body. Nature, by its design, has protected these vital centres by placing them deep inside the body or by covering them with tissues inaccessible to normal attempts of breach.Varmam is a holistic therapy on its own and tackles the body, mind and spirit. A varmam expert understands the underlying links between the body, vital life-force and the mind. Varmams have been classified based on the type of pressure needed to injure: (a) Paduvarmam (varmam due to injury), (b) Thodu varmam (by touch); Thattu varmam (by blows); (c) Thaduvu varmam (by massage); (d) Nakku varmam (by licking i.e. tongue massage); and (e) Nokku (by staring). The widely used and recognised ones are the 12 Paduvarmams and 96 Thoduvarmams; there is less consistency with the other categories simply because of the way of application or the deeper knowledge needed to apply them. In these categories, the Nokku varmam is rarely seen practiced, as those masters who were able to do this are almost extinct. Nokku Varmam exploits the 3-d sense of balance by using subtle movements to induce the eyes of the recipient.[clarification needed] A varmam therapist needs to have a deep knowledge about the body's nerves and physical structure to do an effective treatment. There are only a few therapists existing in this world, and the modern siddha world is trying to preserve this art of healing.

Drugs used by the Siddhars can be classified into three groups: Thaavaram (herbal product), Thaathu (inorganic substances), and Jangamam (animal products). The diagnostic methodology in Siddha treatment is unique as it is made purely on the basis of the clinical acumen of the physician. The pulse, skin, tongue, complexion, speech, eye, stools and urine are examined. This approach is collectively known as "Eight types of examination"; and among the eight, the examination of pulse is very important in confirming the diagnosis.

Generally the basic concepts of the Siddha medicine are similar to Ayurveda. The only difference appears to be that the siddha medicine recognizes predominance of Vaadham, Pitham and Kabam in childhood, adulthood and old age, respectively, whereas in Ayurveda, it is totally reversed: Kabam is dominant in childhood, Vaatham in old age and Pitham in adults. According to the Siddha medicine, various psychological and physiological functions of the body are attributed to the combination of seven elements: first is ooneer (plasma) responsible for growth, development and nourishment; second is cheneer (blood) responsible for nourishing muscles, imparting colour and improving intellect; the third is oon (muscle) responsible for shape of the body; fourth is koluppu/Kozhuppu (fatty tissue) responsible for oil balance and lubricating joints; fifth is elumbu (bone) responsible for body structure and posture and movement; sixth is elumbu majjai (bone marrow) responsible for formation of blood corpuscles; and the last is sukkilam (semen) responsible for reproduction. Like in Ayurveda, in Siddha medicine also, the physiological components of the human beings are classified as Vaadham (air), Pitham (fire) and Kabam(earth and water).

Treatment consists of three distinct categories: Deva Maruthuvam, (divine method); Maanida Maruthuvam (rational method); and Asura Maruthuvam (surgical method). In the divine method, medicines like parpam, chenduram, guru, kuligai prepared from mercury, sulphur and pashanams are used. In the rational method, medicines prepared from herbs like churanam, kudineer, vadagam are used. In surgical method, incision, excision, heat application, bloodletting, leech application etc. are practised. The therapeutic treatment in Siddha could be further categorized into Purgative therapy, Emetic therapy, Fasting therapy, Steam therapy, Oleation therapy, Physical therapy, Solar therapy, Blood letting therapy and Yoga therapy. There is also a branch of the traditional science that deals with traumatology and accidental injuries called Varma. This is based on the notion of more than 100 vital points that are junctions of bones, tendons, ligaments, blood vessels and nerves called Varma points. Pranic energy is found concentrated in these points which, upon manipulation, produce curative effect.

Siddha system has enormous pharmacopoeia containing vegetable, animal and mineral products and treatment techniques consisting in use of 32 types of internal medicines and 32 types of external medicines, application of heat and cold, ointments, potions and poultice, blood letting, counter irritation, bath, suction, manipulative processes such as thokkanam, varma, yoga and concentration on hygiene and diet (pathiam), periodical use of purgatives and emetics, use of drugs which include, apart from herbs, preparations from metals and minerals such as copper, silver, gold, lead and preparations from products of animal origin such as brain, liver, bones, blood, skull, horns of various animals, tissues of reptiles and also Kayakalpa to prevent or postpone greying of hair, formation of wrinkles and ageing, prevention or treatment of diseases, and postponement of death (to any desired length of time). Some empirical treatment techniques under the guise of magic exorcism, incantation, pilgrimage, peregrinations, mountaineering and similar activities have also been in practice since ages past.

There has been a resurgence of traditional medical systems the world over, based on the holistic nature of their approach to healing. The efficacy of indigenous systems has been proved in various contexts. They tend to use locally available, cost effective materials for treatment. Hence, the Siddha system which also has strong cultural and historical bonds with the people of Tamil Nadu is becoming increasingly relevant.