Lord dhanvantri is the incarnation of Lord Vishnu According to Puranas.
When Devas (Gods) and Asuras (Demons) churned the ocean for Amrita (nectar of immortality), it was Lord Dhanvantari who came out of the ocean with a pot of Amrita. Thus, Dhanvantari is clearly a lord who grants long life and immortality.
Bhagavata Purana (2.7.21) calls Dhanvantari as God himself, who is a curer of diseases, who has imparted to the world the knowledge of long life i.e. Ayurveda. He is often represented as a God with four hands (similar to Vishnu) carrying Shankha (conch), Chakra (disc), leech, and a pot containing Amrita. Leeches play an important role in Ayurvedic treatment. Therefore, in Hindu tradition Lord Dhanvantari represents twin aspects of alleviator of diseases and the one who grants long life and immortality. Thus, he is clearly identified with all aspects of health, medicine, and holistic living.
At Prajna Kuteera Ayurveda Tapovan, Dhanwantari Homa is performed every Saturday by the Ruthwiks. As the chants fill the air, the Homa culminates with the Purnahuti at 1 pm followed by the Divya Prasaada.