Abstract:An original error on Huzhang and Tiannanxing in Li Shizhen‘s "Bencao Gangmu" (Compendium of Materia Medica, 1596) is corrected in this paper. The conclusion is that Huzhang in "Shen Nong‘s Materia" (around 200) should be the tuber of Pinellia pedatisecta and Tiannanxing in "Kaibao Bencao" (974) the tuber of Arisaema heterophyllum but they were merged or confused by Li Shizhen. The former, in fact, has been cultivated, marketed, exported and used medically for its high quality, but it has disappeared from herbal literatures owing to Lis error. Therefore, the above-mentioned correction should be accepted in the next edition of Pharmacopoea of the pepole‘s Republic of China.