Chemical substance abuse has tormented mankind throughout history. A number of chemical approaches have been employed in an attempt to treat chemical addiction. Unfortunately, most of these have proven unsuccessful though several chemical entities have been shown to be moderately effective. The naturally occurring alkaloid ibogaine has been reported to interrupt the cravings for alcohol, cocaine and opiates. Other alkaloids from Tabernanthe iboga, such as ibogamine and tabernanthine, provide insight into the structure activity relationship at the different receptors believed to be involved in addiction. The synthetic iboga alkaloid congener, 18-MC, also shows potential as an anti-addictive agent without the hallucinogenic effects of ibogaine. Additionally, acamprosate, BP 897, GBR12909, lofexidine and memantine have shown promising results in the treatment of addiction. All of these leads provide a start for the medicinal chemist to design anti-addictive agents, since currently no drugs are approved in the U.S. for the treatment of addictions to cocaine, methamphetamine, other stimulants or PCP.