overexpression of P-glycoprotein (Pgp) plays a crucial role. Herein, a novel class of ocotillol-type amide derivatives has been designed, synthesized, and evaluated for their ability to reverse MDR. The structure-activityrelationship of the reversal activity was analyzed. Ten compounds showed promising chemo-reversal ability, among which the 24R-ocotillol-type amide derivative 6c with an N-Boc-hexanoyl