Srimad Bhagavatam Canto 09, Chapter 17, Text 04

SB 9.17.4

kasyasya kasis tat-putro
 rastro dirghatamah-pita
dhanvantarir dirghatamasa
 ayur-veda-pravartakah
yajña-bhug vasudevamsah
 smrta-matrarti-nasanah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The son of Kasya was Kasi, and his son was Rastra, the father of Dirghatama. Dirghatama had a son named Dhanvantari, who was the inaugurator of the medical science and an incarnation of Lord Vasudeva, the enjoyer of the results of sacrifices. One who remembers the name of Dhanvantari can be released from all disease.
Srimad Bhagavatam Canto 09, Chapter 17, Text 01-03
Srimad Bhagavatam Canto 09, Chapter 17, Text 05