Evodia refers to the Chinese herb wuzhuyu, the immature (nearly ripe) fruit with stems removed from Evodia rutaecarpa. The herb is one of the few classified in traditional Chinese medicine as hot in nature, and some texts indicate that it is "extremely hot” (Hsu, et. al., 1986). While the description of hotness is primarily from the effect the herb has on the tongue, herbs with this property are said to dispel internal coldness, a type of therapy that alleviates pain and rectifies the flow of qi. Evodia is classified along with cinnamon bark, dry ginger, Sichuan pepper (zanthoxylum; from the same plant family as evodia) and other hot peppers in a small section of the Materia Medica dedicated to herbs for dispelling chill and warming the interior.