Because of anecdotal reports in which ibogaine eliminates opioid withdrawal symptoms in humans, we studied this phenomenon in the rat model. Ibogaine (5,10, 20 and 40 mg kg−1, s.c.) was administered 15min before naloxone (0.5 mg kg−1, s.c.) in morphine dependent rats (3 days after the s.c. implantation of a 75 mg morphine pellet). Of the 12 withdrawal signs scored, the only significant changes observed after ibogaine (compared with vehicle control) was a decrease in grooming (10 mg kg−1) and an increase in teeth chatter (5 mg kg−1). In spite of ibogaine's apparent interaction with several neurotransmitter receptor systems, it does not alleviate opioid withdrawal in this animal model at non-tremor-igenic (5 and 10 mg kg−1) or tremorigenic (20 and 40 mg kg−1) doses.