[en] The effective hepatic blood index was noticed as a factor which decides liver function in pre- and postoperative periods of liver resection. The authors devised a method in which the index was calculated in an area of the liver from hepatic and splenic uptake of ₁₉₈Au-colloid and discussed its clinical significance. The normal value for the index was (183 +- 13) x 10^-₃/min. Following wide resection of the liver, the index decreased in proportion to the amount resected. The preoperatively predicted index for postoperative residual part of the liver roughly correlated with the actual postoperative index by a correlation coefficient, 0.67. The lower limit of the index for survival was estimated to be 50 x 10^-₃/min. The effective hepatic blood flow index can be a valuable indicator of liver function, especially on deciding the extent of liver resection. (Ueda, J.)