Combined enzymodiagnostic program--estimation of total activity of blood serum enzymes aspartate aminotransferase (AST), alanine aminotransferase (AAT), alkaline phosphatase (AP), gamma-glutamyl transferase (gamma-GT), glutamate dehydrogenase (GDH), acetyl cholinesterase (ACE), butyryl cholinesterase (BCE)--was studied to evaluate its diagnostic validity in surgical clinic. In mechanical jaundice of various origin mean values of the enzymatic activities studied as well as the enzymatic coefficients were distinctly altered as compared with control values: AST/AAT, gamma-GT/AST as well as the newer coefficients BCE/ACE, AP/gamma-GT, (formula; see text). The jaundices of tumoral and non-tumoral genesis caused markedly dissimilar alterations in the coefficients AST/AAT and (formula; see text). The data of enzymological analysis may be used for differential diagnosis in jaundices.