17(R)-Resolvin D1 (17(R)-RvD1) is an aspirin-triggered epimer of RvD1 that reduces human polymorphonuclear leukocyte transendothelial migration, the earliest event in acute inflammation, with equipotency to RvD1 (EC50 = ~30 nM). 17(R)-RvD1 exhibits a dose-dependent reduction in leukocyte infiltration in a mouse model of peritonitis with maximal inhibition of ~35% at a 100 ng dose. In contrast to RvD1, the aspirin-triggered form resists rapid inactivation by eicosanoid oxidoreductases. 17(R)-RvD1 methyl ester is a methyl ester version of the free acid which may act as a lipophilic prodrug form that will alter its distribution and pharmacokinetic properties. The methyl ester moiety is susceptible to cleavage by intracellular esterases, leaving the free acid.