ABSTRACT
The Chinese crude drug “Mu-tong, ” “Mokutsu” in Japanese, is standardized as the stem of <i>Akebia quinata</i> Decne. and <i>A. trifoliata</i> Koidz. of Lardizabalaceae in the modern Japanese pharmacopoeia. On the other hand, the botanical origin of Mu-tong is rather complicated in China, and many different plants among several families are used as a kind of Mu-tong. The herbological study clarified that Chinese doctors in the Tang dynasty had changed the original name “Tong-tsao” to “Mu-tong, ” meaning “woody Tong-tsao, ” to distinguish it from another type of Tong-tsao derived from the soft pith of <i>Tetrapanax papyrifera</i> Koch of the family Araliaceae plant. The classical botanical origin of Mu-tong is <i>Akebia</i> plants. Though the pith of <i>Tetrapanax papyrifera</i> is used as “Tong-tsao” in modern China, Akebiae Caulis is the true botanical source of ancient prescriptions such as those found in Shang-han-lun, an ancient Chinese medical book.