Methanolic extract of Abrus precatorius leaf was subjected fractionation using the column chromatography. Six fractions of this plant were eluted, and their fluorescent characteristics, wavelengths and Rf values, noted. The fractions were administered to female wistar rats at 5mg/kg orally for eight days. Fraction 4, sub-fraction 4a caused a significant (p<0.05) increase in the index of libido (mount frequency, 2.05 ± 0.16; mount latency, 23.48 ± 0.19; intromission latency, 3.05 ± 0.28 and lordosis quotient, 87%±1.0). The cGMP and Nitric oxide levels in the glans clitoridis of the female wistar rats post treatment with the fractions, arginine, yohimbine and sildenafil were also measured. Treatment with Sildenafil, Arginine, Yohimbine and F4a produced the 114.2%, 87.7%, 57.1% and 71.4% increase respectively, in NO levels; cGMP levels were also markedly increased in the Sildenafil, Arginine, and F4a treated groups. There was also a significant reduction in the systolic blood pressure and heart rate of female rats during the treatment period with f4a, Sildenafil citrate, Arginine and Yohimbine, possibly due to a vasodilatation effect. In conclusion, sub - fraction 4a may be responsible for the libido- enhancing activity of the plant extract.