Different extracts (Petroleum ether, chloroform and ethanolic) of leaves of C. gigantea were investigated for locomotor activity. The result shows that the ethanolic extract of the leaves of C. gigantean was found to be effective. The acute toxicity study revealed safely of the extract up to a dose of 2000 mg/kg. The ethanolic extract of leaves of C. gigantea at a dose of 100, 200 and 500 mg/kg was selected for CNS activity. The anticonvulsant properties were studied on maximal electroshock test (MES), strychnine and PTZ-induced convulsions model. Ethanolic extract protected rats against maximal electroshock (MES) induced seizures. But had no effect against strychnine and PTZ-induced seizures. Exploratory behaviour after being treated with leaves extract, there was a significant decrease in exploratory behaviour of rats as compared to control. The motor in coordination and loss of muscle tone in rota-rod test and incline test. The result shows that the ethanolic extract of leaves of C. gigantea was found to be effective against the CNS activity. The CNS depressant effects of the leaves of C. gigantea may be due to the presence of more than one principle and their synergistic properties. The ethanolic extract of this plant is attractive material for the development of a potent phytomedicine for the CNS disorder