A Study of the effects of the root components of Angelica gigas Nakai (Umbelliferae) on voluntary activity in mice has confirmed that there are: 1) MeOH soluble extract, MeOH insoluble extract, decursin and decursinol were antagonized against the voluntary activity in mice pretreated with a dose of caffeine natrium benzoate 30mg/kg. 2) MeOH insoluble extract showed higher depressant effect than MeOH soluble extract. 3) The depressant activity of decursinol was significantly more highly effective than that of decursin.