As Lin Chun-ching points out, ancient folk medicine can be divided into four major systems: Arabian, Indian, Greek, and Chinese. The largest point of commonality between these four systems is in the use of natural medicine. With the growth of the silk road and expansion of East-West trade, mutual exchanges of these substances began to take place.
林俊清指出，就民族藥學而言，古代醫學分阿拉伯、印度、希臘、中國等四大體系；它們的一大共同特點就是使用天然藥物，且隨絲路的發達和東西貿易的開拓而彼此交流。