The mouse has several distinct advantages as an experimental model for study of the cochlear blood flow (CBF) in the mammal, particularly for studies involving genetic manipulation, development and aging factors. In this investigation we evaluated the effects of selected vasodilating agents on CBF using laser-Doppler flowmetry. Sodium nitroprusside, hydralazine and pentoxifylline were applied topically on the round window (RW) or systemically by a subcutaneous injection. Topical application of sodium nitroprusside and hydralazine elevated CBF significantly, while systemic administrations of these two drugs failed to elevate CBF consistently. Pentoxifylline did not change CBF following topical application but increased CBF slightly following systemic administration. Age and gender did not influence the CBF response to topical application of sodium nitroprusside.