Work from our laboratory has shown that an enteric helminth infection can act as an adjuvant to prime for a Th2-biased response to a typically tolerogenic form of dietary antigen. Helminth infection did not, however, prime for an allergic response. Using a model in which systemic anaphylactic symptoms and antigen specific IgE are induced in C3H/HeJ mice by repeated intragastric administration of peanut antigen with the mucosal adjuvant cholera toxin we showed that an enteric helminth infection protects against the development of food allergy. Helminth-dependent protection against allergy was abrogated when the helminth-infected, allergen-sensitized mice were treated with neutralizing antibodies to IL-10. Recent work from our laboratory and others has implicated helminth induced immunoregulatory cells in protection against allergy. We will discuss the characteristics of the immunoregulatory cell populations that have been described and the mechanism(s) by which they may function in the suppression of allergy.