The influence of fresh Kola-nut (Gooroo-nut) extract on locomotor activity of laboratory male mice was studied using direct ethological observations. The Kola extract was injected intraperitoneally (I.P.) to the experimental animals and behavioural measures were made at 15, 30, 60 and 120 min intervals post injection. It was observed that a medium dose (5 mg/kg) significantly increased the locomotor activity whereas a low dose (2.5 mg/kg) had no effect and a high dose (10 mg/kg) showed depressive effects on the locomotor activities. The results suggest that the Kola extract induces biphasic changes in the locomotor activity of mice depending on the dose and the treatment duration.