The authors tested the psychic abilities of workers occupationally exposed for several years to high environmental aluminium concentrations with psychomotor ability tests, Wechsler's test of intelligence and Bender's test for estimation of cerebral damage. Slower psychomotor reaction and dissociation of oculomotor coordination were found in the exposed workers. Also, exposed workers had reduced memory ability and their mental and emotional balance was disturbed. The observed changes in psychomotor and intellectual abilities could be a consequence of the long-lasting toxic effects of aluminium.