To study the immune response of offspring rats after parental rats exposure to allergen. MethodsParental BN rats were divided exposure and non-exposure to allergen groups. The offspring rats were randomly divided into OVA group, control group respectively, OVA and control were daily administrated at the dose of 1 mg/ml OVA or at the dose of sterile water by gavage for 6 weeks. Blood samples were taken on the 2^nd, 4^th, and 6^thweeks from the orbital plexus, and centrifuged to obtain sera for analyzing specific IgG and IgE.On the 3^rd, 5^thweeks, blood samples were taken to obtain plasma for analyzing histamine. In addition, the changes of gut permeability were determined.ResultsAllergenic responsecould be induced by provoke allergen OVA in BN rats when parental rats were non-exposure to allergen OVA, include specific IgG,IgE increasing and histamine increasing. However, little allergenic response be provoked by OVA in BN rat when parental rats were exposure to allergen OVA.ConclusionThe immuneresponse of offspring BN rats were weaken after parental rats exposure to allergen.