SummaryMacerated decoction extracts of Zea styles exert consistent hypoglycemic effects in fasting rabbits provided they are administered parenterally. Repeated daily subcutaneous administration of the extract to non-fasting rabbits produces even fatal hypoglycemia. The statistical pattern of the hypoglycemic effect of Zea styles compares well with that of crystalline insulin and the distribution is of the gaussian normal curve. The concomitant toxic effects of the hypoglycemic extract, especially when administered intravenously, cannot be accounted for by its blood sugar reducing principle since we could separate the toxic effect from the blood sugar reducing effect.