Rehmannia root is often sold by its Hanyu Pinyin (pinyin) name of sheng dì huáng, which means “yellow earth.” The earliest written record of its use in Traditional Chinese Medicine dates to the Han Dynasty (200 BCE). Its species name is obtained from the term “glutinous,” a reference to the sticky nature of the roots when introduced to warm water or wine.
Dubbed "the kidney's own food,” Rehmannia is a cooling herb reputed to balance Yin. Because it is said to strengthen Jing (the life force), it is regarded an important longevity herb.