The discriminative stimulus properties of ibogaine were investigated in rats trained to discriminate phencyclidine (PCP; 2.0 mg/kg, I.P.) from saline under a two-lever fixed-ratio (FR) 32 schedule of food reinforcement. Ibogaine (5.6-17.6 mg/kg, I.P.) showed a complete lack of substitution. Ibogaine (0.5-4.0 mg/kg, I.M.) also failed to generalize in rhesus monkeys trained to discriminate PCP...