A study was planned to see if the Panax Ginseng has any influence upon the general activity of rats. Seventeen male rats (mean body weight: 204 g) was divided into a ginseng group (N=9) and a saline group (N=8). Once a day for 5 days they received subscutaneously 0. 5m1/100g body weight of ginseng extract solution (4 mg of ginseng alcohol extract in 1 ml of saline), and same amount of saline, respectively. For 20 days beginning from the 1st day of medication on, each rat received activity measurement by means of beam interruption method. Following results were obtained : 1. Activities at night (6 p.m. to 6 a.m. next morning) and in 24hours on the 10 th, 12th, and 13 th day were significantly increased in the ginseng group compared with activities of the saline group. 2. Summed total night and 24-hour activities observed for 15 days after termination of medication were also significantly augmented in the ginseng group compaired with those of the saline group, although no remarkable difference existed between the 2 groups with regard to the summed total daytime activity. It is inferred that the ginseng augments general activity of rats especically at night.