The ability of a selective cholecystokininB (CCKB) receptor antagonist, CI-988, to block benzodiazepine withdrawal effects was examined in mice. The discontinuation of twice daily administration of diazepam (1 mg kg-1, i.p.) induced withdrawal anxiogenesis and a proconvulsant effect. In contrast, no such effects were seen following withdrawal from similar administration of CI-988. However, CI-988 dose-dependently (0.001-1.0 mg kg-1, s.c.) antagonized both the anxiogenesis and the proconvulsant effect following diazepam-withdrawal.