Streptococcus pyogenes (group A Streptococcus,         S. pyogenes) is an important human pathogen responsible for mild suppurative throat and skin infections to life-threatening invasive diseases. A number of experimental trials have examined the biological and antitumor effects of S. pyogenes Su strain on various tumor cells and animals, as well as humans. The present study considered the potent anticancer properties of a streptococcal preparation possessing biological activities in vitro and in vivo and summarized the overall effects of streptococcal preparations in antitumor actions.