利用正交试验方法，研究了影响粉防己中汉防己甲、乙素的提取效率的各种因素，得到的最佳提取条件为：用含33.3%氨水的无水乙醇溶液浸泡8h，超声震荡提取4h。在此条件下测得的汉防己甲素的含量为0.678%，乙素的含量为0.616%。汉防己甲、乙素的含量用高效液相色谱（HPLC）检测，最低检出限分别为3.87×10^-3和2.48×10^-3mmol/L。

Several factors influencing the extraction of tetrandrine and demethyltetrandrine from Chinese medicinal herbs, Stephania tetrandra S. Moore were studied by means of Ortogonal method. The optimum Condition was eight hours steeping, in 33.3% ammonia in absolute alcohol for four hours under ultrasonic agitation. Tctrandrine aud demethyltetrandrino were detected by HPLC. The contents were 0.678% and 0.616%, the detection limits were 3.87×10^-3and 0.48×10^-3 mmol/L respectively.