The aim of the study was to determine the effect of the application of hyperbaric oxygen therapy on the course of an infection with group A type T-3 hemolytic β streptococcus. Experiments were carried out on Porton white mice and in vitro blood plates. General and local infections with streptococci were induced in animals. The infected animals were treated with hyperbaric oxygenation. The lethal effect of infection was significantly inhibited using hyperbaric oxygenation on the first and second day following the infection.