A battery of neuropharmacological experiments showed the hot water extract of Ocimum sanctumLinn. (Labiateae) had a depressant effect on the central nervous system (CNS), but the aqueousextract showed no effect on it. The hot water extract reduced the spontaneous locomotor activity,exploratory head dipping, propulsive locomotion and exploratory ambulation as well as prolongedthe pentobarbital induced sleeping time. The depressant effect starts from 60 minutes after thedrug administration and continued to 180 minutes. The drug may exert central depressant effectby interfering with the function of the cortex.