The resulting mismatch of assignment and abuse potential, possibly due to "radical" political ideology, obscures significant differences in drug effects and therefore stifles meaningful public participation in evaluating the benefits, risks, and use of psychoactive substances. A traditional measure of drug toxicity is the therapeutic index, a number derived by dividing the lethal dose of a substance by the effective dose. For various reasons, the therapeutic index is not a very sensitive metric of toxicity or health impairment. Further, scientific estimates of both toxicity and addiction potential are inferential rather than actuarial; they are based on inferences from atypical human populations or from nonhuman animal studies rather than on observations of normally healthy people in natural social settings. With respect to the regulatory framework, the Comprehensive Drug Abuse Prevention and Control Act, known as the Controlled Substance Act, designates the Food and Drug Administration as the agency to evaluate the abuse potential of suspect substances and to specify control procedures. The DEA assigns substances to one of five schedules that range from higher to lower abuse potentials. For example, heroin, LSD, and marijuana fall under Schedule I, while amphetamines and cocaine fall under Schedule II. Drugs in Schedules III through V all have accepted medical uses, have decreasing physical or psychological abuse potential relative to the first two schedules, and do not require special handling beyond usual medical prescription and drug storage procedures. The DEA is authorized to transfer substances between schedules. The author concludes that DEA classifications portray the health risks of many psychoactive substances in a way that lacks candor and clarity. Research on the health risks of psychoactive substances is reviewed, and political aspects of risk reduction regulation are examined. 67 references, 25 notes, 1 table, and 1 figure