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Stimulated Raman scattering (SRS) of OH stretching vibrations of water molecules is investigated when an intense pulsed beam is focused in liquid water. The SRS is emitted before the phase transition from liquid to plasma, and an enhanced vibrational spectrum is obtained at around 3400 cm^-1, the main peak of water in the liquid phase. Despite the strong and perturbing excitation condition, the temperature dependence of the forward SRS spectrum indicates that the SRS sensitively reflects the slight changes of the local hydrogen-bonding network environment in liquid water. The local network environments in dilute ethanol solutions (1−3 mol %) are investigated by utilizing the enhanced vibrational spectrum. Little change is observed in the peak shift of the SRS, indicating the that the perturbation is relatively small as compared to that induced by structure-breaking solutes such as KCl. There is, however, a clear decrease of the intensity on the higher frequency side of the SRS band in ethanol solutions. Although direct evidence is not observed for the well-known hypothesis that there is enhancement of the ordered icelike or clathratelike structures around hydrophobic groups, the SRS spectra indicate that reinforcement of the hydrogen-bonding network structure is induced by adding a small amount of ethanol molecules.