Abstract: Antitumor agent which comprises as the principal agent a mixture of organic compounds having amino group and silyl group (reffered to as silamines) and represented by structural formulae with Adriamycin. Use of silamines in the form of a mixture with Adriamycin, which is an anti-cancer agent showing a potent effect but having extremely serious side effects, makes it possible to highly potentiate the anti-cancer properties of Adriamycin. As a result, the dose of Adriamycincan be reduced and thus its side effects can be relatively relieved as compared with the case where it is used alone. [wherein R1, R2, R3, R4, R5, R6, R7 and R8 represent each hydrogen or C1-10 alkyl, aryl or aralkyl, or the pair of R1 with R2 and that of R5 with R6 may be bonded via alkylene, allylene or aralkylene.

Abstract: Antitumor agent which comprises as the principal agent a mixture of organic compounds having amino group and silyl group (reffered to as silamines) and represented by structural formulae with Adriamycin. Use of silamines in the form of a mixture with Adriamycin, which is an anti-cancer agent showing a potent effect but having extremely serious side effects, makes it possible to highly potentiate the anti-cancer properties of Adriamycin. As a result, the dose of Adriamycincan be reduced and thus its side effects can be relatively relieved as compared with the case where it is used alone. ##STR1## ?wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8 represent each hydrogen or C.sub.1-10 alkyl, aryl or aralkyl, or the pair of R.sub.1 with R.sub.2 and that of R.sub.5 with R.sub.6 may be bonded via alkylene, allylene or aralkylene.