Abstract
This review will focus on alteration of cytokine networks, in particular of proinflammatory and regulatory cytokines, induced by bacterial toxins secreted in the human gastrointestinal (GI) tract. Deregulation of cytokine networks is probably involved in the alteration of the homeostasis of the indigenous flora. Particular attention will be focused on alteration in the regulatory cytokine cascade that can be responsible for pathological conditions induced by Clostridia.