an abstract ABSTRACT AIM: To find the optimal combination and evaluate the interaction between the curcumin (Cur) and adriamycin (ADM) in vitro antitumor effects. METHODS: According to the experimental design and data characteristic, the parameter method and the response surface approach combined with a simulation technique were used to analyze the pharmacodynamic interactions of in vitro antitumor effects in the combination of Cur and ADM at different dose ranges. RESULT: The dose-effect relationship of combination in the ratio of ADM:Cur = 1:3 showed significant change in comparison with used alone. in combination of adriamycin (ADM) (0.7～1.38 μmol•L-1) and curcumin (Cur) (2.04～4.07 μmol•L-1) with a fixed ratio (1:3)，the interaction nature indicated a synergism. With the doses of combination increasing, the combination showed an addition. Computer simulation showed the difference between the observed and expected effect decreasing trend with the dose of Cur increasing from 2.04 to 16.29 μmol • L-1. The response surface analysis shows an optimal combination is the combination of Cur 18.50 μmol • L-1 and ADM 3.89μmol • L-1 with the ratio of 1:0.2. CONCLUSION: The parameter method combined with the response surface analysis can provide richer and more reasonable information, and it is helpful to quantitative design for a drug combination therapy and to describe the natures and degree of drug interaction.