Which term refers to substances used for medical treatment, especially drugs?

The term that refers specifically to substances used for medical treatment, particularly drugs, is "medication." This term encompasses a wide range of pharmaceutical compounds prescribed by healthcare professionals to diagnose, treat, or prevent illnesses and health conditions. Medications can include over-the-counter drugs, prescription medications, and even certain therapies that utilize drug components.

While "therapies" refers more broadly to treatments that may include various methods and interventions, and "interventions" can encompass any action taken to improve a situation, including therapies or lifestyle changes, "medication" is specifically focused on pharmaceutical agents. "Substances" is a more general term that could refer to anything from chemicals to food items, lacking the specific connotation of medical usage associated with "medication." Thus, "medication" is indeed the most appropriate choice when discussing substances specifically designed for medical treatment.