Since Taplin started the 131Ⅰ-RB liver function study in 1954, Beak and Eyler reported scanning using Ⅰ-131 RB for the first time for differentiation of etiologic factor of clinical jaundice. Recently Mamori studied about the serial blood clearance rate of liver after injection of 131Ⅰ-BSP intravenously. In Yonsei University, we have selected 131-BSP and 131-RB liver and abdominal scanning in clinically suspicious obstructive jaundice. We analyzed 27 cases of 131-BSP, RB scanning and reviewed other literature about the 131Ⅰ-RB, or 131-BSP liver and abdominal scanning. Result: 1. In normal control group, gall bladder uptake of 131Ⅰ-BSP was done within 30 minutes, and the colonic uptake was within 2hrs in general scanning, and suggestive of normal patency of biliary tree. 2. In Hepatocellular group of liver cirrhosis and hepatitis, diffuse decreased uptake of mottling densities in initial liver scan, and there had been delayed excretion into G.B. or colon, however, there wa no definitive evidence of biliary obstruction. 3. In Hepatoma and liver abscess group, discrete cold area in initial parenchymal liver scanning, however, intestinal excretion was visualized within 2 hours and suggesting biliary patency. 4. Extrahepatic obstructive jaundice such as cholangiocarcinoma, hepatoma involving porta hepatis and choledochal cyst fail to excrete 131Ⅰ-BSP, or 131Ⅰ-RB into intestine and suggesting obstructive jaundice. 5. In unconfirmed jaundiced group Ⅰ-131 BSP or 131Ⅰ-RB show delayed but all excreted into intestine suggesting delayed biliary patency.