Group A streptococcal infections are frequent and most often benign. Severe invasive infections due to this microorganism have nevertheless been reported with increasing frequency in various countries for several years. Moreover, a toxic shock-like syndrome has recently been recognized and characterized in such infections. Two cases of invasive group A streptococcal infections (one primary peritonitis and one toxic shock syndrome) are reported to increase a better understanding of this disease in the light of a review of the pertinent literature. This is hoped to contribute to better management of what is a growing problem for many physicians who are nowadays no longer familiar with the broad spectrum of group A streptococcal infections.