Long term administration of anticonvulsants is sometimes associated with impairment of the humoral and/or cellular immune response. Furthermore, certain well known adverse reactions to antiepileptics may have an immunotoxicological origin e.g. lymphadenopathy, pseudolymphoma and systemic lupus erythematosus. However, two important questions remain unresolved. First, the possibility that epilepsy per se might be primarily associated with immune alterations makes it difficult to assess the pathogenetic role of a specific drug, especially in a patient population usually on multiple drug therapy. Secondly, the clinical relevance of some of the observed immunological abnormalities is still highly controversial. This review is intended to give an outline of the present state of knowledge on the effects of anticonvulsants on humoral, cellular and nonspecific immunity, with particular regard to some of the major clinical conditions that have been ascribed to drug-induced immune dysregulation, such as pseudolymphoma and systemic autoimmune diseases. The immunotoxic potential of anticonvulsants appears to be low, and immunological monitoring is not usually required except in patients with known immune defects.