Siddhar (Tamil: சித்தர் cittar, Sanskrit: siddha) describes a self-realised human being, who has attained spiritual powers called Siddhis. Their main objective however, was to experience Sivam, the supreme consciousness, in their respective human frame,[3] and share this knowledge with others, interested in following their path.

An ancient system of healthcare, now known as Siddhar Medicine, evolved from the Siddhars' understanding of the human body, in relation to the natural world. The basic tenets of this system are food and lifestyle. It is a holistic and sustainable way of delivering healthcare, as it is largely preventative and focused on rejuvenation and prolongation.

There is a saying, common amongst those familiar with the system, 'unave marunthu, marunthe unavu' (food is medicine, medicine is food). A rustic form of healing, inspired by Siddhar medicine, is practiced today by experienced elders in the villages of Tamil Nadu, referred to as 'paatti vaitthiyam' (grandmother's medicine) 'naattu marunthu' (folk medicine) and 'mooligai marutthuvam' (herbal medicine). The Siddhars also used pulse-reading to identify the origin of illnesses and physical conditions.

Their Powers:

The Siddhars had both major and minor Siddhis, these are described in detail in various tantric texts, like the Tirumantiram. They had the power to convert their mass to energy and thereby achieve teleportation to different galaxies without any external means. They were also able to move their awareness into lifeless bodies, reanimating them; as in the case of Sundaranandar transferring his being into the body of the dead cowherd Moolan, because the cows Moolan had been tending to were mourning their loss and as such Sundaranandar felt sorry for them.

1. Anima -- To reduce one's self to become as tiny as the atom within an atom
2. Laghima -- To make one's self become as light as vapour
3. Mahima -- To have the grace of Sivam and become great and glorious in one's self
4. Prapti -- To transcend one's desires
5. Prakamya -- To 'transmigrate' one's self into the mortal coils of other beings
6. Isavatam -- To be lord of all creation, to be omni-potent and be inextricably one with Sivam
7. Vasitvam -- To be in all things, to be omni-pervasive, to perceive Sivam in all beings that come within one's reach
8. Kamarutatva -- To be everywhere and pervade all space, to be omnipresent and visit all worlds with one's physical body inert and stationary