The aim of the present study was to define the behavioral correlates of chronic exposure of adult rats to flumazenil (4 mg/kg/day X 21 days in drinking water). In the holeboard test, performed on day 13 of drug treatment, the animals showed a significantly greater interest for the holes under which objects were placed than for the holes without objects (p less than 0.03), while there was no such difference in the control group. In the plus-maze test, the flumazenil-treated animals spent significantly more time on open arms and left less fecal boluses than the controls when tested in the third week of treatment and 24 hours after flumazenil withdrawal. In the drinking-punishment test, conducted on days 3, 6 and 10 after drug withdrawal, the drug-exposed animals, following shock experience, did not significantly alter their unpunished drinking in subsequent trials, while the control rats significantly reduced (p less than 0.003) their unpunished drinking. Also, the punished drinking revealed a significant "anticonflict" effect of prior exposure to flumazenil (p less than 0.006) which was still observed 6 days after drug withdrawal. There were no group differences in the home-cage food and water consumption during flumazenil treatment; also, the drug treatment had no effect on nociceptive threshold. In summary, chronic treatment with a benzodiazepine receptor antagonist, flumazenil, increased exploratory activity and had a lasting anxiolytic effect.