A new glycoside was isolated from Acanthopanax chiisanensis Nakai (Araliaceae) leaves and its biological activity was investigated. The new glycoside was tentatively assigned the structure of Asecotriterpenoid glycoside, $C_{48}H_{76}O_{19}$ m.p. $208~209^{circ}$ and named chiisanoside. Chiisanoside exhibited non-toxic effects and significant antihistaminic activity. It was found that chiisanoside showed the antidiabetic activity against epinehrine-and alloxan-induced diabetes, decreased the toxicity of $LD_{50}$ by ephedrine hydrochloride and promoted the elimination of chloramphenicol from blood. Chiisanoside also increased the survival rate in rats intoxicated by carbon tetrachloride from death and led to re-establishment of normal enzymatic function. In the histopathological studies, chiisanoside improved fatty degeneration and parenchymal cell necrosis of the liver induced by carbon tetrachloride in rats.