Sushrutha, the legendary surgeon and practitioner of Ayurveda, said he had been told by the Supreme One that Dhanvantari would divide Ayurveda into eight parts. Velukkudi Krishnan elaborated on these divisions in a discourse. The eight divisions are Shalya, Saalakya, Kaaya chikitsa, Bhuta Vaidhya, Kaumara, Agada Tantra, Rasayana and Vaajeekarana. These divisions can be matched to specialisations that we find in modern medicine. Thus Shalya is surgery. Shaalaakya deals with diseases affecting the face and neck. Kaaya Chikitsa talks of examining patients and diagnosing their ailments. Bhuta Vaidya deals with problems of the mind. In other words, it is about psychological problems. Kaumara is nothing but paediatric medicine. Agada Tantra studies toxins in the body, infections like fevers, snake bites and so on. Rasayana is concerned with studying herbs to make medicines with them and to study about prolonging life. Vaajeekarana deals with fertility and reproduction. Ayurveda addressed two concerns — how to treat those afflicted with diseases and how to prevent people from falling prey to diseases. In Ayurveda food itself is seen as medicine. If we take the right sort of food and eat normal proportions, instead of overeating, then we can be healthy.
We get a human body, on the basis of our karma. And we cannot know what past karma of ours has determined our birth. After we are born, we come into contact with many objects and with many people. Suffering or pleasure can result from these connections and contacts. We are born with the qualities — sattva, rajas and tamas. But we can change our qualities. Vibhishana was born an asura, but developed sattvik qualities. Ancient texts dealt with relief for bodily ills and also with release from the samsaric cycle.