Abstract: Aconite root is an important Chinese traditional drug, often used as an analgesic agent. Of the 162 species of Aconitum grow in China, the roots of about 40 species are used medicinally. These Aconite roots may be classified into five categories: 1. Caowu group (21 species); 2. Xueshang Yizhihao group (5 species); 3. Bangga group (2 species); 4. Niubian group (7 species); 5. Miscellaneous group (5 species).The morphological characters of the roots of these five groups are described. After a histological study of the roots all the above mentioned species may be classified into 3 types by the arrangement of vascular bundles in transverse section of the root:Type 1. A single siphonostele, dissected and collateral.Type 2. A polystele composed of several siphonosteles arranged in a circle.Type 3. A number of sehizosteles arranged in circles, formed by separation of the original collateral siphonostele due to the formation of a circle of corky tissue, each surrounding 1～3 bundles. The tissue between the corky circles will gradually die and decay. In this way, it appears that the root is composed of strands lying together more or less like the strands of a rope.A table listing the shape of the root, its histological type, the presence or absence of stone cells and the shape of the cambium ring is provided.