Abstract: ObjectiveThe pur pose of this study was to test the hypothesis that the buckwheat grown in an epidemic area caused endemic breast enlar gement disease.The blood serum prolactin(PRL),follicle-stimulat ing hormone(FSH),luteinizing hormone(LH),estradiol(E2),progestin(P),testosterone(T)in rats were analysed using redio immunoassay(RIA).ResultsThe results indicated that the level of serum PRL in expertimental rats fed with the accused buckwheat was much significantly higher than that in the controls(P<0.01),and LHalso higher(P<0.05),and P was much significantly lower than that in the controls(P<0.05).ConclusionThis results accorded with the case with endemic breast enlargement disease.It is suggested that the buckw heat grown in an epidemic area maybe cause endemic breast enlargement.