七層塔係本省常用之民間藥，能清熱、涼血、消腫、解毒、利水、殺蟲，常被用於肝炎、咽喉腫痛、咳血、吐血、尿血、腹水、痔瘡、癰疽等之治療。關於七層塔之基源，據甘偉松、許鴻源、邱年永、張光雄等人之調查認為係唇形科(Labiatae)植物，Salvia plebeia R. Br.之根莖或全草。但據著者們收集市埸品及現地調查之結果，發現除了上述植物外，尚有他種同名異物品出現在市埸上，為究明市售七層塔之基源，卻保藥效及開發生藥資源，而從事生藥學之研究。由比較組織學的研究，依外部形態和內部構造之特徵，確認了台灣市售七層塔之基源為節毛鼠尾草(Salvia pleveia R. Br.) 和印度羅勒 (Ocimum gratissimum L.) 。 Chhlt-chan-than is one of the folk medlclnes in Talwan, used as, detumescence, antidote, diuresis, insecticide. It has been used in the treatment of hepatitis, sorethroat, hemoptysis, hematemesis, hematuria, ascites, hemorrhoid etc. The origin of Chhit-chan-than has been assumed by kam, Hsu, Chiu, Chang to be derived from the root, stem and entire plant of Salvia plebeia R. Br. of Labiatae. However, in vestigation of the folk medicine collected on Taiwan market showed two plants used as chhit-chan-tan on Taiwan market To clarify the origin of Chhit-chan-than on taiwan market, the comparative anatomy was examined. The external morphological and internal structure characteristics indicated that the origins of "Chhit-chan-than" are derived from the following species, Salvia plebeia R. Br. and Ocimum grotissimum L.