After the hemodynamic comparison of venous air volume in 32 rabbits, the following conclusions were derived. 1) The precordial doppler ultrasonography was most sensitive and end titdal CO₂ pressure was statistically decreased at 0.1 ml/kg of air. 2) The mean arterial pressure was suddenly decreased at 1 minute after injection of more than 0.25 ml/kg of air, and was furether reduced according to the time. 3) The arterial PCO₂ was continuously increased and statistically different from 0.25 ml/kg of air, and the arterial PO₂ was suddenly decreased to about 1/3 of the control data. 4) The pulse rate was statistically decreased at more than 0.5 ml/kg of air and shown peaked p wave, arrhythmias, ST depression and premature ventricular contraction on the EKG. There 4 dead rabbits at 1.0 ml/kg of air, so we could conclucle that the fatal dose of rabbits was more decreased than that of the dogs in venous air embolism.