Throughout history, people have used plants and minerals to change their body chemistry. Coffee, chocolate, tea, wine, beer, aspirin, allergy medicine, vitamins—all of these change human body chemistry. All of these could be considered drugs.

But when you see signs that say "Say NO to drugs," they're not talking about all drugs. Some drugs hurt your body. Some can cause serious or permanent damage after even one use. Many are addictive, making the user dependent on them.