the purpose of this study was to determine if the stress created by a generalized motor seizure was significant enough to alter the immune response. criterion measures of anitgen binding capacity (abc) to human serum albumin (hsa) were obtained from 39 female and 36 male satinder's heterogenous strain (shs) albino rats. within 30 seconds after a second hsa injection (booster), rats were either injected with metrazol to produce generalized (motor) convulsions, or with cyclophosphamide, an immunosuppressive drug (comparator treatment). a third group served as a saline-injection control and a fourth as an undisturbed control group. multivariate analysis of variance (manova) demonstrated a highly significant immunosuppression 4 days later in rats that had displayed brief motor convulsions and had been administered cyclophosphamide. injection and undisturbed controls did not differ significantly from each other. by the 10th day after the booster and treatments, abc measures for the drug treated rats (metrazol, cyclophosphamide) were not significantly different from controls. however on the 10th day females showed significantly higher abc measures than did males. the degree of immunosuppression seen on day four was moderately correlated to the severity of the seizure observed. these results suggest that the seizuring of an animal is a stressful event capable of suppressing humoral immunity, and that the degree of suppression is positively correlated to the severity of the seizure.