Abstract: In this paper, the median-effect principle was used to design a computer programto evaluate the combination chemotherapy effect in vitro. This program requires fewer tests and cannot only determine whether the interaction of two drugs is synergic, but also analyse the synergicefficiency with changing dosages. It can be used as a reference for the design of combination chemotherapy in clinical practice.

Key words: Combination chemotherapy, Drug sensitivity test, Median-effect principle