National Institute on Drug Abuse
Nida: Research Report Series: Hallucinogens and Dissociative Drugs
An advanced level report which defines hallucinogens and dissociative and explains their effects.
US National Library of Medicine
Medline Plus: Dextromethorphan
At this site read about dextromethorphan, an ingredient in many over-the-counter cough suppressants, or antitussives. This website provides brief responses to several queries about dextromethorphan including, "Why is this medication...