Ayurveda, the science of health and longevity, is very ancient and a great contribution of Bharat (India) to the world medicine. Dhanvantari is said to be the originator of this science.
Considered as a partial manifestation of Lord Vishnu and the physician of the Gods, Dhanvantari rose from the ocean of milk at the time of churning it(Samudra Mathana) with the amritakalasha or pot of ambrosia in his hands.
He was a reborn as Divodaasa, the king of Kasi and composed a standard and basic work of Ayurveda comprising eight sections.
Dhanvantari has been mentioned in Ramayan, Harivamsha and Bhagavatam. In course of time, “Dhanvantari” became a title for the very best of physicians, one who has mastered the administration of 300 medicines, the other two titles being bhishek(expert in 200 medicines) and vaidya(expert in 100 medicines).
Nineteen works authored by Dhanvantari have found mention in other standard works. Some of them are Chikitsa Deepika, Balachiktse, Dhanvantari NIghantu, Vaidya Bhaskarodaya and Ayurveda saravali. Dhanvantari Nighantu is said to be the most ancient work.

Dhanvantari icons are shown in various postures. A two armed figure holding amritakalasha or pot of ambrosia is common. He is also shown with four or six arms holding the emblems of Vishnu – Shankha and Chakra. In one of the more curious forms, he is shown holding a leach in one of his hands suggesting blood-letting or surgery.