17-Phenyl-18,19,20-trinor-PGD2 (17-Phenyl-PGD2) is an analogue of prostaglandin D2 (PGD2;). 17-Phenyl-18,19,20-trinor-PGD2 is a potent inhibitor of platelet aggregation caused by aenosine diphosphate (ADP), with the IC 50 of 8.4 μM (PGD2 IC 50 = 18.6 nM). 17-Phenyl-18,19,20-trinor-PGD2 is a weak agonist of cyclic AMP accumulation.