Rhubarb (Rhei Radix et Rhizoma), one of the commonly used Chinese herbal medicines (CHMs), which is called Dahuang in Chinese, is derived from the dried roots and rhizomes of Rheum officinale Baill., R. palmatum L., or R. tanguticum Maxim. ex Balf.[1]. It is traditionally used as a decoction either alone or together with other crude drugs (such as Aurantii Immaturus Fructus, Magnoliae Officinalis Cortex and Gardeniae Fructus) for oral administration