In rats with 2-week obstructive jaundice the sensitivity to endotoxin was studied and the effect of a single dose of endotoxin on histological development in the kidney, liver and spleen was also investigated. We were tested the effect on accumulation and distribution within organs, of fibrinogen labelled with radioactive iodine 125. We showed an increased sensitivity to endotoxin in obstructive jaundice. The cause of death in most rats was acute circulatory failure during the course of endotoxic shock, without clinical features of disseminated intravascular coagulation. In the isotope study, after endotoxin administration there was a specific dynamic increase of fibrinogen accumulation in the kidneys of rats with obstructive jaundice. We proposed, that the cause of the kidney changes during the course of obstructive jaundice could be the local activation of intrarenal coagulation.