Acute toxicity and sedative action of water-soluble fractions obtained from Zizyphus seeds were estimated in mice. Very weak toxic effect was found in all the fractions. Fractions DZ-191, DZ-193, and DZ-18 showed some sedative action in a climbing test. Significant potentiation of hexobarbital-induced anesthesia was found in DZ-191, DZ-193, and ZM fractions. Significant antagonistic effect to caffeine-induced hyperactivity was found in DZ-193 and ZM fractions. Only ZM showed a slight decrease of hole crossing after repeated oral administration for 3 days.