Evaluation was carried out on the action of different antibiotics on the release of cytokines. Experiments were done in vitro on monocytes and on human lymphocytes. Results show that the majority of the antibiotics tested are able to induce the release of one or more cytokines from their respective producing cells. Among the beta-lactams the most active were the cephalosporins (cephalexin, cefamandol, ceftazidin, and a sulbactam-ampicillin combination) in inducing the release of TNF, IL-1 alpha, and IL-6 from monocytes, and releasing IL-4 and IFN-tau from lymphocytes. The sulbactam-ampicillin combination and cefamandole were extremely active in the production of IFN-tau. Among the lincosamides, clindamycine notably stimulated the release of TNF and IL-6, while lincomycine induced a notable increment of IL-4 from monocytes. Teicoplanin is a very strong inducer of TNF, IL-1 alpha and IL-6.