The synthetic analogous of the prostaglandins are utilized in the obstetrical and gynecological therapy for multiple purposes. 4 lots with 12 nonpregnant female rats were use: the Ist received 25 g/kg/day isopropyl ester PGF2; the IInd lot received 50 g/kg/day isopropyl ester PGF2; the IIIrd lot received 50 g/kg/day optic active cloprostenol; the IVth lot was the witness lot. The medication was intraperitoneally (i.p.) administrated in a unique daily dose. Prostaglandin F2 analogous at small doses (25 micrograms/kg/day) induce vasodilating effects on the ovary blood vessels and functional luteolysis rather than structural luteolysis. Both of the prostaglandins analogous at doses of 50 micrograms/kg/day present obvious vasodilating and luteolytic effects, although the intensity of the phenomenon is not the same, cloprostenol is more active, inducing a more obvious vasodilatation and luteolysis.