In the US, a "drug" is:

  • A substance recognized by an official pharmacopoeia or formulary.
  • A substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease.
  • A substance (other than food) intended to affect the structure or any function of the body.
  • A substance intended for use as a component of a medicine but not a device or a component, part or accessory of a device.
  • Biological products are included within this definition and are generally covered by the same laws and regulations, but differences exist regarding their manufacturing processes (chemical process versus biological process.

In Europe, the term is "medicinal product", and it is defined by EU law as: "(a) Any substance or combination of substances presented as having properties for treating or preventing disease in human beings; or

(b) Any substance or combination of substances which may be used in or administered to human beings either with a view to restoring, correcting or modifying physiological functions by exerting a pharmacological, immunological or metabolic action, or to making a medical diagnosis.

Classification[