Where are the four ancient medicines?

Anhui Bozhou Jiangxi Zhangshu Henan Baiquan Henan Yuzhou Hebei Anguo Hubei Qichun

The above-mentioned cities are recognized as the "Drug Capital of China" in China, with a long history and developed pharmaceutical trade. There are tens of millions or even hundreds of millions of yuan of drug transactions every year, and the local drug transaction income is also one of the main local fiscal revenues. Every year, a local drug fair is held, which is a distribution center for drug trading. As for which are the four major drugs, there are different opinions.