[Action of essential oils of chamomile, cinnamon, absinthium, mace and origanum on operant conditioning behavior of the rat].

The Chamomile, Cinnamon, Absinthium, Mace, Origanum essential oils have been experimented on rat's operant conditioning behaviour. At the highest doses all the oils caused a depressive effect (probably due to toxicity) while at the lowest doses they caused weak or doubtful effects. Only the Origanum oil caused a depressive effect which clearly seems related to a direct action on the CNS.