A pharmacological comparison between cannabidiol (CBD) and four CBD derivatives, namely CBD-aldehyde-diacetate (I), 6-oxo-CBD-diacetate (II), 6-hydroxy-CBD-tri-acetate (III), and 9-hydroxy-CBD-triacetate (IV) was carried out in mice. Protection against maximal electroshock convulsions, potentiation of pentobarbital sleeping-time and reduction of spontaneous motor activity were the effects measured. All 5 compounds were equally potent in potentiating barbiturate sleeping time at doses ranging from 6.25 to 100 mg/kg. At 12.5 and 25 mg/kg only CBD and IV were able to decrease significantly the spontaneous motor activity. CBD, II, III and IV were also active in protecting mice against electroconvulsive shock at doses of 100-200 mg/kg, although at the larger dose CBD and compound II were the most efficient. Compound I was toxic, killing about half of the animals within 24 h after injection.