Dhanvantari (धन्वन्तरि) is the physician of the devas in Hinduism. He is regarded to be an avatar of Vishnu. He is mentioned in the Puranas as the god of Ayurveda.
During his incarnation on earth, he reigned as the King of Kashi, today locally referred to as Varanasi. Dhanvantari is also identified as the great-grandfather of Divodasa, a mythological King of Kashi in the Vishnu Purana.
According to the ancient Sanskrit work Vishnudharamottara, Dhanvantari is a handsome individual and is to usually be depicted with four hands, with one or two of them carrying a bowl of amrita, the elixir of immortality. Dhanvantari is depicted in a stark resemblance to Vishnu, with four hands, holding the shankha, chakra, jalauka (leech), and a pot containing amrita. He is often shown with a leech in his hand rather than the scriptures, indicating the historical practice of bloodletting.
Some texts describe him as holding a conch, amrita, medicinal herbs, and a book of Ayurveda.
The Bala Kanda of the Ramayana and Bhagavata Purana state that Dhanvantari emerged from the Ocean of Milk and appeared with the pot of amrita (elixir of immortality) during the Samudra Mathana, whilst the ocean was being churned by the devas and the asuras, using the Mandara mountain and the serpent Vasuki. The pot of amrita was snatched by the asuras, and after this event, Vishnu's avatar, Mohini, appears and takes the nectar back from the asuras. It is also believed that Dhanvantari promulgated the practice of Ayurveda. Of special mention here is the treatise of Dhanvantari-Nighantu, which completely elucidates Dhanvantari's medicinal plants.
The Brahmanda Purana describes the origin of the physician deity:
Let the origin of Dhanvantari be heard, O Brāhmaṇas. He was born formerly when the ocean was being churned, for the sake of nectar. At the outset, he was born before the Kalaśa (pot). He was encircled by a halo of glory all round. On seeing him having accomplished his task suddenly, Viṣṇu who was standing by said—“You are born of water”.