Chen Yan (1121-1190), whose courtesy name was Wuze, was a famous doctor in the Song Dynasty (960-1279). He was from Hexi town in Jingning county, Lishui, Zhejiang province.

His medical book, Sanyinji - Disease Theory, was written about in History of the Song Dynasty. The book, with nearly 240,000 words and 18 rolls, was divided into 180 categories and recorded more than 1,050 medical prescriptions for various diseases and problems such as internal, surgery, ophthalmology and otorhinolaryngology, gynecology and pediatrics.