Lycopus lucidus

Lycopus lucidus is a species of plant in the Lamiaceae family. The dried rhizomes are used in Traditional Chinese Medicine, where they are known as Lycopi rhizoma or le zan and have a reputation for promoting blood circulation and energy (qi), and preventing water retention. They are said to have a 'warming' property, and have a mild bittersweet flavor. Media related to Lycopus lucidus at Wikimedia Commons