Dhanwantari is the physican of the gods, the promulgator of the Ayurveda.
Dhanwantari arose at the time of the churning of the ocean of milk, holding the cup of Amrita, the life-giving elixir. He also carriede the Jalooka (leech, used by Ayurvedic practitioners for blood letting) and the Vaishnava symbols like Srichakra and Sankh. To some he is really an incarnation of Lord Vishnu.
Dhanwantari was also born as a king of Benares, who brought medical science to the world. Images of Dhanwantari are often found in the shrines of Ayurvedic docters. He is also considered as a great surgeon who taught Ayurvedic surgery to Susrutha, the father of Ayurvedic surgery.