Yi Yin (dates of birth and death unknown) is also known as Yi Zhi or A Heng."Yin"is an ancient official title, similar to"admin-istrative assistant". He lived in the early period of the Shang Dy-nasty (1600 BC1046 BC), and regarded as an politician, physician and head chef.1 He is the author of Classic of Herbal Decoction or Yi Yin's Classic of Herbal Decoction.