The effect of the 20 coded amino acids on the proliferation processes in the organotypic tissue culture of rat liver development has been investigated. 3 low - molecular hydrophile amino acids - Arginine, Glutamic acid, Asparagine - at 0,05 ng/ml concentration stimulated the cellular proliferation; 11 amino acids suppressed the proliferation due to the development of apoptosis. Thus, the coded amino acids are not only the structural elements of the proteins, but can participate in the regulation of the cellular cycle. The data obtained demonstrate, that the amino acids or their combinations can be used for liver tissue pathology treatment. The effective action of small encoded amino acids doses reduces risk of the side effects when using drugs created on these amino acids basis (2 figs, bibliography: 14 refs).