The rats were fed with albuminous concentrate from the genetically modified soybean 40-3-2 ("Monsanto Co", USA) 1.25 g/rat/day for 5 months. Their blood, urea and liver were investigated to measure total protein and glucose levels, aminotransferase and alkaline phosphatase activities, pH, relative density and creatinine level in the urea, as well as hepatic enzyme activity of the I and II phases of xenobiotic metabolism, and the whole and non-sedimentated lysosomal enzyme activities. The lasting albuminous concentrate supplementation from the genetically modified soybean to the rat's diet has been shown to modify hepatocyte membrane function and enzymatic activity within physiological standards. It was not harmful to the adaptation systems.