The histological research of male bai zhi showed that it had severe lignified while the tissues secereting the volatile oil and the coumarin ( secretory cavity ) were very little . the results of extractive test also showed that the principle constituent of male bai zhi was lower than the common evidently 公白芷的组织研究表明其木化程度高,而与挥发油和香豆素类成分密切相关的组织(分泌腔)又较少,白芷浸出物含量测定的结果也表明,公白芷中有效成分的含量明显低于一般白芷。