The authors performed a comparative biochemical study of some enzymes of lysosomic origin (hyaluronidase, N-acetyl-beta-D-glucosaminidase, beta-glucosidase, beta-galatosidase and acid phosphatase), of the state of enzyme substrate system N-acetylneuraminic acid---aldolase of neuramic acid and of the activity of lactatedehydrogenase (soluble in cytosol and bound on mitochodria) in the liver, lungs and blood serum of rats at various regimens of the inhalation action of CCl4. On the basis of results obtained they determined the biological importance of the change of activity of enzymes differently localized in cells at the adaptation of an organisme to the noxious action of CCl4.