What is defined as a drug?

A drug is best defined as a substance intended to affect the body’s normal functioning. This definition encompasses various categories of substances, including prescription medications and over-the-counter drugs, which are specifically designed to alter physiological processes or treat medical conditions.

The focus here is on the intended effect on bodily systems, which can include promoting healing, alleviating symptoms, or modifying behavior. This definition allows for a broad application across both legal and illegal substances because it centers on the impact on the body rather than the legality or form of the substance.

Looking at the other options, a food supplement may enhance performance but is not primarily intended to affect normal bodily function as classified under 'drugs.' A beverage containing alcohol does have psychoactive effects but is not categorized strictly under the traditional definition of a drug since it’s often regarded within the context of recreational use. Lastly, while a natural remedy might treat illness, it is not necessarily classified as a drug unless it has a defined medicinal purpose recognized by regulatory bodies.