Shen Nung's book was not actually written in its earliest form until the Neo-Han dynasty, A.D.25-221, the tea reference being added after the seventh century when the word ch`a came into use.
In an allegory, the book quotes one of the emperors of the Han dynasty as saying: "The use of tea grows upon me surprisingly: I know not how it is, but my fancy is awakened and my spirits exhilarated as if with wine." This makes it evident that the tea drink had progressed in Lu Yu's time from the earlier rank decoction of unprepared green tea leaves into a more inviting infusion.
The travelers speak of tea as the common beverage of China and tell how the Chinese boil water and pour it scalding hot upon the leaf, adding, "The infusion preserves them from all distempers."(*7) It is evident the Chinese of the ninth century infused the leaf much the same as to-day, and that they continued to regard it as possessing medicinal properties.