Having noticed psychotic traits in some patients showing incoercible vomiting due to antineoplastic drugs we have thought of establishing a therapy with lithium in the days preceding the therapeutic cycle in order to reduce the emetic events. The effectiveness of lithium carbonate (600 mg/mq p.o./day for one week) in the prevention or reduction of vomiting induced by antiblastic therapy has been checked in comparison with metoclopramide and domperidone in 40 patients. In the group pretreated with lithium, 80% of the cases showed favorable results. In the control groups, on the contrary, the efficacy of the antiemetic therapy has shown to be of lesser importance (55%). The undesirable side-effects of lithium appear to be irrelevant. We therefore think that pretreatment with lithium may become, in selected cases not affected by traditional antiemetics, of great importance in the control of emetic symptomatology.