Deoxycholic acid derivatives were identified as P-glycoprotein modulators. All derivatives were evaluated through daunorubicin accumulation in K562/R7 cells. All derivatives were evaluated through potentiation of doxorubicin in K562/R7 cells. Intrinsic toxicity of all derivatives was evaluated on K562 cells. Some deoxycholic acid derivatives are more active and less toxic than cyclosporine A.