What is a drug?

• A. A chemical that only treats disease.
• B. Any substance (solid, liquid or gas) that brings about a physical and/or psychological change to the body.
• C. A substance that has no impact on the body.
• D. An herbal remedy with no side effects.

Answer: (B)

A drug is any substance that changes how the body or mind works. This broad idea includes medicines used to treat illness as well as other substances like caffeine, alcohol, nicotine, or cannabis, which can all bring physical or psychological changes. The important point is the effect on the body or brain, not whether the substance is legal or prescribed.

That’s why the broad description fits best: it captures that drugs can be medicines or everyday substances that alter functioning. The other statements are too narrow or incorrect: some drugs aren’t just for treating disease, some substances do have effects, and herbal remedies can have side effects or interactions even if they’re natural.