大葉桑寄生（Scurrula liquidambaricolus（Hayata）Danser ）之葉，先以乙醇萃取，其濾液再以熱水抽取，所得的水抽出物再依序用正己烷(Hexane)、氯仿(chloroform)、正丁醇(n-butanol)及醋酸乙脂(Ethyl acetate)進行分配(partition)。由各種抽出物對兔空腸作一試驗，發現醋酸乙脂抽出物A及B均能對小腸產生顯著的抑制作用。故知在大葉桑寄生中存有長效性肌肉鬆弛物（long-acting muscle relaxing factor），它對腸平滑肌有顯著的抑制效果。 Two factors obtained from Scurrula liquidambaricolus were compared by their effects on smooth muscle contraction. The inhibition of Factors A and B on smooth muscle contraction was found to be long-acting. The difference and Similarity of these two factors as well as their application was discussed. Factor B had a strong inhibition activity. Thus, in the leaf of Scurrula liquidambaricolus had long-acting muscle relaxing factors.