In this study, a preparation was developed which continuously monitored thef2−f1,2 f1−f2,and3f1−2 f2distortion products in guinea pigs, in response to various contralateral and ipsilateral tones and broadband noise. A consistent decline over time in the quadratic distortion product,f2−f1,with continuous ipsilateral stimulation was observed, confirming previous findings by Kirk and Johnstone [Hearing Res.67, 20–34 (1993)]. Broadband noise applied to the contralateral ear simultaneously increased both the magnitude and the rate of decline. This effect was shown for primaries across all frequencies tested (f2from 2–16 kHz,f2/f1ratio of 1.26), though a maximal effect was found forf2of 4 kHz. Experiments using contralateral tones demonstrated a half-octave shift in the frequency specificity of this effect. A more “immediate” suppression effect on2 f1−f2(0.6 dB) was found in animals awakening from anesthesia, though this was even larger forf2−f1(5.1 dB). Extended ipsilateral stimulation with contralateral noise results in completely diminishingf2−f1to the noise floor. These findings suggest an adaptive process within the cochlea that may be modulated by efferent stimulation. A model relating the various even- and odd-order distortion products to outer hair cell receptor potentials is presented.