99mTc-DAIDA is superior to other cholotropic radiopharmaceuticals. As radiochromatographic examinations with various systems showed, it is secreted by the hepatocytes into the bile as an unchanged anion. In a study of hepato-gastroenterologically selected patients (n = 45) values for liver function parameters such as Tmax' T/2, time of appearance in gall-bladder and duodenum were in the group of patients without any hepato-biliary disease (x +/- S.D.): 15.5, +/- 5.2 min, 30.8 +/- 8.2 min, 13.5 +/- 6.1 min, and 22.0 +/- 10.8 min. The clearance determined after comparison of different defining regions and types of calculation in this group was 323.8 +/- 145.8 ml/min x 1.73 m2 (x +/- S.D.); the renal excretion competitive with the hepato-biliary elimination amounted within 51 min p.i. to 5.15% of the injected activity. The values of the several time-parameters as well as the participation of the kidneys in the 99mTc-DAIDA excretion increased substantially in patients with intrahepatic jaundice, but only slightly in the group of other liver cell diseases. It was not possible to determine the various liver function values in patients with extrahepatic jaundice. Because of their large spread within the different groups these parameters were without diagnostic relevance in the individual case. The hepato-biliary sequential scintigraphy with 99mTc-DAIDA appears to find its main use in morphologic diagnostics.