Srimad Bhagavatam Canto 08, Chapter 08, Text 34

SB 8.8.34

sa vai bhagavatah saksad
 visnor amsamsa-sambhavah
dhanvantarir iti khyata
 ayur-veda-drg ijya-bhak
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
This person was Dhanvantari, a plenary portion of a plenary portion of Lord Visnu. He was very conversant with the science of medicine, and as one of the demigods he was permitted to take a share in sacrifices.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Srila Madhvacarya remarks:
 
tesam satyac calanartham
 harir dhanvantarir vibhuh
samartho ’py asuranam tu
 sva-hastad amucat sudham
 
Dhanvantari, who was carrying the jug containing nectar, was a plenary incarnation of the Supreme Personality of Godhead, but although he was very strong, the asuras were able to take the jug of nectar from his hands.
Srimad Bhagavatam Canto 08, Chapter 08, Text 33
Srimad Bhagavatam Canto 08, Chapter 08, Text 35