Bisbenzylisoquinoline alkaloids (23) including tetrandrine, isotetrandrine and berbamine were studied for various biological activities. Comparisons of biological activities were made in bacterial cells, blood cells, HeLa human cervical cancer cells and the whole mouse to obtain better ideas concerning the correlation between activity and chemical structure. From the results of the present investigation, it is suggested that at the present stage a definite structure-activity relationship, as reported by Kupchan, et al., is hardly delineated, though certain structure requirements for the manifestation of antitumor activities were noticed.