To evaluate the antiemetic effectiveness and toxicity of a novel congener of metoclopramide (MCP), alizapride (AZP), 29 patients receiving cisplatin (50 mg/m2) alone or with adriamycin (40 mg/m2) were entered into a randomized cross-over trial comparing moderate-dose AZP (2 mg/kg for 4 doses) administered alone or with dexamethasone (DXM) (8 mg for five doses) vs a standard combination of MCP (1 mg/kg for four doses) and DXM (as above). With the dosage and schedule used, AZP provided only limited antiemetic protection, with less than 10% of the patients free of emesis. The AZP-DXM combination was significantly more effective than AZP alone in reducing the intensity of the emesis (P less than 0.03). The incidence, however, was statistically unaffected. The additional toxicity of DXM was negligible. Except for the patients' preference for MCP-DXM (P less than 0.01), no differences could be found between the DXM-based regimens, although a trend towards a better antiemetic effect with the MCP combination was evident. The benzamide-related dystonic reactions were equally distributed. Among the 11 patients affected there were 6 who required specific treatments. Unfavourable prognostic factors in the patient population could provide a reasonable explanation for the disappointing antiemetic protection obtained with all the regimens evaluated in this study.