Our experimental studies show that the IC50 on she action potential of isolated frpg sciatic nerve blocked by pH7.4 and 4.8 tetracaine solution are 0.34mg/ml and 0.67mg/ml (p<^6.01) respectively. The ED50 on rabbits nasalmucous membrames anesthetized by pH 7.4 and pH4.8 tetracaine solution are 0.30+0.03 and 1.1+0.15mg (p<0.001) respectively. The ED50 of rabbits corneia anesthetized by pH 7.4 and 4.8 tetracaine solution are 0.45+0.05 and 1.2+0.18mg (p<0.001) respectively. Both tet-racaine solution of pH 7.4 and 4.8 given same large doses(5mg) to nasal mucous me-mbranes haye no different effects on heart rate

blooa pressure and respiration wit-tin 60 minuts