Sixty cases of routine contrast enhanced CT were analyzed about the utilities of positive pressure drip infusion method using high concentration contrast media 350 mgI/ml, 100 ml. They were divided into three groups and each twenty cases were received positive pressure drip infusion method using Iohexol 350 mg/ml, 100 ml (350PP), positive pressure drip infusion method using Iohexol 300 mgI/ml, 100 ml (300PP) or conventional drip infusion method using Iohexol 300 mgI/ml, 100 ml (300DI). Enhancement effects of the liver parenchyma, the aorta and the spleen at upper, middle and lower levels of the liver were evaluated with increased attenuation on pre- and postcontrast CT. And intrahepatic contrast was evaluated with attenuation difference between liver parenchyma and intrahepatic vessels on postcontrast CT. In result, 300PP kept better enhancement effects and obtained better intrahepatic contrast than 300DI at the each level of the liver, and 350PP was still better than 300PP. The analysis of relationship between intrahepatic contrast and body weight suggested that 300PP was the optimal choice for the cases with 40-50 kg body weight and 350PP was for the ones with 50-60 kg as the infusion method of routine contrast enhanced CT. And the dose of contrast media seemed to be more needed for the cases over 60 kg body weight. 350PP and 300PP were concluded as useful, safe and simple methods for routine contrast enhanced CT of the liver.