We have reported that a diazepam binding inhibitor (DBI)-like peptide is released by the aversive quinine stimuli 'Chem. Senses 25 (2000) 739'. To determine the effect of DBI on the fluid intake, we injected a DBI peptide fragment into the fourth ventricle in mice. DBI suppressed the intake of 5% sucrose, water and 0.9 mM quinine-HCl and the preference for 0.05% saccharin. Administration (i.p.) of flumazenil, a benzodiazepine receptor antagonist, 20 min before the injection of DBI (i.c.v.) antagonized the suppressive effect of DBI on the intake and the preference for saccharin. We also studied the dose dependency of the effect of DBI on the intake of 5% sucrose. Injection of DBI in excess of 3 microg suppressed the intake of 5% sucrose in mice. Furthermore, injection of DBI (i.c.v.) increased the aversive response to 0.9% NaCl in the taste reactivity in mice. These results suggest that DBI affect the preference to food.