In the years 1981-1986 bacteriophage therapy was applied in 550 cases (100 treated in 1986) of suppurative bacterial infections. Positive results were obtained in 508 cases (92.4%). In 38 cases (6.9%) a transient improvement was observed and in 4 cases (0.7%) phage treatment proved ineffective. Considering that majority of patients (518 cases, 94.2%) were resistant to antibiotic treatment, the results of phage therapy may be regarded as favorable.