It has been shown that contralateral auditory stimulation(CAS) along medial efferent system pathways may alter cochlear micromechanics and hence affect click evoked otoacoustic emission (CEOE) in humans. CAS reduced CEOE in humans, but several parameters alter this effect ; middle ear pathology, idiosyncracy, sleep, intensity of the sound level evoking the CEOEs, type of the CAS, etc. However it is the only non-invasive way to explore the medial olivocochlear system in humans. For the exploration, pure tones were presented to the contralateral ears of 30 normal hearing ears during the acquisition of CEOE using a Kemp ILO88 Otodynamic Analyser. The contralateral ear was stimulated with pure tones of 250, 500, 1,000, 2,000 and 4,000Hz at 20, 40, 60 and 80dB sound pressure level(SPL), respectively. Echo response and reproducibility showed contralateral suppression in a manner directly related to the intensity of CAS(p=0.0062, p=0.0000) in all frequencies. However, they were not related to the frequency of CAS(p=0.4633, p=0.7831). Excluding the data of contralateral stimulation with 80dB SPL, echo response and reproducibility were also related to the intensity(p=0.0234, p=0.0000), but not to the frequency of CAS(p=0.4123, p=0.7506).