Superantigens (SAgs) are virulent polypeptides that are produced by a variety of infectious organisms. They are capable of causing nonspecific T cell activation by circumventing normal antigen processing in the human host. The genetic makeup of the host plays a role in conferring susceptibility or protection against SAgs. They are linked to a variety of conditions, ranging from toxic shock syndrome to recurrent toxin-mediated perineal erythema. The early recognition of signs and symptoms of SAg-mediated illnesses is important to ensure prompt medical treatment.