Si Junzi Tang has four ingredients: ginseng, licorice, atractylodes (baizhu), and hoelen (fuling); it is derived from Lizhong Wan (Pill for Warming the Center) of the Shanghan Lun by replacing the warming, spicy ginger with the bland, neutral hoelen. As a result of this single herb change, the earlier chill-dispelling prescription is altered to form…