Demand reduction refers to efforts aimed at reducing the public desire for illegal and illicit drugs. The drug policy is in contrast to the reduction of drug supply, but the two policies are often implemented together. Some discussions of demand reduction make a distinction between policies that address single issues (such as public "knowledge-of-harms") or are short-term interventions (such as in-school programs), and those that approach drug demand as a complex issue with multiple social risk factors. Some economists such as Milton Friedman argue that due to the law of supply and demand, reducing demand is the only effective way to reduce drug use long-term. It is questionable, however, whether demand reduction programs actually reduce demand.
In June 2000, Canada replaced the black-and-white warning messages on cigarette cartons sold in that country with color graphic depictions of the consequences of smoking, mandating that they cover 50% of the front surface of each carton. Each tobacco product features one such image from a series, which includes people dying in hospitals, rotting mouths, and dissected body parts depicting tumors, along with simple bold messages stating that cigarettes cause cancer, mouth disease, impotence, and harm babies. International research supports the efficacy of such warning messages.