The effects of alcohol and other psychotropic drugs on eye movements are reviewed with particular attention to the possible relevance of these effects for traffic safety. Alcohol has been shown to have diverse effects, including reduction of the velocity of both saccadic and smooth pursuit eye movements, increased saccadic latency, impairment of convergence and induction of nystagmus. These effects probably contribute to impaired visual information processing, which reduces driving ability. Barbiturates have been reported to produce effects similar to alcohol, and the effects of benzodiazepines and opioids seem to be more limited but still substantial. Marihuana has relatively little effect on eye movements.