Twelve healthy volunteers were randomly allocated to receiving in a double-blind cross-over fashion levocabastine eye drops (0.5 mg/ml solution) and placebo. They were advised to instill 2 drops per eye, four times daily. Each treatment was administered for a period of 1 week. Before and after each treatment period psychomotor function was assessed using Critical Flicker Fusion Test and the Choice Reaction Time Test. At the same time intervals a subjective evaluation of sedation was given using a Visual Analogue of Sedation. Both objective and subjective measurements showed that no significant treatment effects could be detected. It is concluded that repeated instillations of levocabastine eye drops are devoid of any sedative side effects.