A hot-H2O extract of rhizomes of Anemarrhena asphodeloides, the Japanese sino-medicine "chimo," lowered the blood glucose level in alloxan-diabetic mice. Hypoglycemic activity-guided fractionation isolated a new glycoside, pseudoprototimosaponin AIII [1], which was compared with chemically known prototimosaponin AIII [2]. These compounds exhibited hypoglycemic effects in a dose-dependent manner in streptozotocin-diabetic mice but showed no effects on glucose uptake and insulin release, suggesting that the hypoglycemic mechanism may be due to inhibition of hepatic gluconeogenesis and/or glycogenolysis.