Morphological changes of the sensory hairs due to transtympanic infusion of fluids with different osmotic pressure were scrutinized using color guinea pigs. Animals were sacrificed after four days fluid injections and examined by scanning E. M. Transtympanic infusion of distilled water (0 mosmol), physiological saline solution (285) and 5% (148), 10% (315) saccharose solutions demonstrated no abnormality on the sensory hairs. 20% saccharose solution (720) and 2.4%NaCl solution (743) revealed moderately change of twistning, adhesion and fusion of the sensory hairs. 30% saccharose (1224) and 4%NaCl solution (1248) demonstrated ovious changes the sensory hairs.