This article reported the results of eight series of animal experiments. In each series, the rats were divided into two groups: the experimental group was fed on corns and vegetables from endemic districts; the control group, from non-endemic districts. The composition of the foodstuffs was the same in the two groups. 375 albino rats were used in the experimental group, and 315 rats in the control group. The observation period was 8-13 weeks.The results showed that the incidence of myocardionecrosis had increased, the heart weight was comparatively larger, the mortality rate was higher, growth was stunted and the weights of the thymus and brown fat were lower than those of controls. The differences between experimental and control groups were stastistically singnificant. Such difference was not due to the composition of foodstuffs, but was closely related to the districts, from where the corns and vegetables were obtained. The results of these eight series of experiments were similar, and with very good reproducibility. It seemed that there were some myocardiac necroti-zing and growth inhibition factors in the corns and vegetables from the Keshan disease endemic districts.