Ibogaine, a naturally occurring monoterpene indole alkaloid is administered for opioid detoxification, as well as disorders of use of other substances. The mechanism of action of ibogaine is apparently novel, and it is of interest as a possible prototype for the development of innovative pharmacotherapy of addiction. Clinical evidence regarding treatment outcomes is limited.Methods: In this observational study 30 patients received ibogaine HCl administered as a single mean dosage of 1540 ± 920 mg at two clinics located in Mexico. The Subjective Opioid Withdrawal Scale (SOWS) was used to assess detoxification outcome. Addiction Severity Index Composite (ASIC) scores were computed at baseline and at 1, 3, 6, 9, and 12 month follow up posttreatment. The persistence of a treatment effect was evaluated by comparison of ASIC scores at 1 month to subsequent months using equivalence tests with a margin of 10%.Results: Pretreatment SOWS scores (31.0  11.6) decreased to 14.0  9.8 following ibogaine treatment (t=7.07; p< 0.001). Improvement in ASIC Drug Use, and Legal, Family/Social and Psychiatric Status scores at 1 month relative to pretreatment baseline was sustained in subjects retained in the study at later time points. The subset of 12 subjects with 75% or greater reductions relative to pretreatment baseline of ASIC Drug Use scores at 9 or 12 months had a history of 2.0 ± 1.6 prior treatment episodes utilizing conventional modalities.Conclusion: Ibogaine appeared effective in opioid detoxification. Group statistics and individual trajectories indicated a sustained posttreatment effect on opioid use in a subset of subjects, including some for whom other treatments had previously been unsuccessful.