Peony is known simply as shaoyao when not distinguishing between red and white peony; shao is the term referring to the peony plant, while yao means medicine; hence shaoyao means: the medicine made from peony. Red peony is the whole peony root with its reddish thick outer bark (epidermis) included; white
peony is the peeled root; the bark is stripped off to reveal a powdery white to pink underlayer. The way in which white peony is produced is described in the Advanced Textbook on Traditional Chinese Medicine and Pharmacology (6): "The root of the three or four year old plant is dug and collected in summer and autumn, washed clean with the rhizome and fibrous roots [rootlets] removed, and the rough epidermis scraped off, cooked slightly in boiling water, and finally dried in the sun."