The studies covered 21 workers chronically exposed to benzine and tetrachloroethylene. The average age of subjects was 45.6 years, whereas average duration of exposure--17.8 years. All the test workers underwent determinations of half-time of the decrease in the activity of Bengal rose labelled J-131 in blood. In addition, a number of biochemical and enzymatic tests have been carried out. The obtained results have been compared to those in a group of people non-exposed to any noxious substances, in whom no liver lesions had been diagnosed by biochemical tests. No changes in the test biochemical parameters have been found in the group of workers chronically exposed to organic solvents, as compared to the non-exposed group. In the test group only statistically significant differences were found in T1/2 values of CBJ-131 test, as compared to controls, which may be indicative of a slight impairment of liver parenchyma in the test workers; on the other hand, no interrelation between T1/2 CBJ-131 and duration of work in exposure has been demonstrated.