What is a medication defined as?

A medication is defined as an approved therapeutic agent that is applied to or introduced into the body to diagnose, cure, mitigate, treat, or prevent disease. This definition encompasses a broad range of substances, including over-the-counter drugs, prescription medications, and therapeutics that have undergone rigorous testing and approval processes to ensure their safety and efficacy in treating various health conditions.

The other options describe narrower contexts that do not encompass the full definition of medication. For example, requiring a prescription is not a defining characteristic of all medications; many effective medications, such as those available over-the-counter, do not require a prescription. Similarly, dietary supplements are not classified as medications; while they may support health and alleviate certain symptoms, they do not undergo the same regulatory scrutiny as medications. Lastly, placebos serve a different purpose in clinical trials—they are used to evaluate the effectiveness of an active medication rather than being considered a therapeutic agent themselves. Therefore, option A is the most comprehensive and accurate definition of what constitutes a medication.