Experiments set up on rabbits showed that with their intravenous administration in a dose of 10 mg/kg antiphein, aethimizol, allilnorantipheins and propylnorantiphein catalize the activity of the pentosophosphate mode of the carbohydrates transformation. The character of the action and the intensity of the effect depend on the features distinguishing the chemical structure of the substances, of particular importance here being changed conformation of the molecule.