Medicinal products are substances that are used in humans or animals for therapeutic or diagnostic purposes. They are intended to prevent diseases, relieve complaints or to prevent such diseases or complaints in the first place. These substances can act both within (e.g. administration of tablets) or on the body (e.g. in the case of hormonal intrauterine devices that release the corresponding hormone in the body). Contrast agents that are used to make anatomic structures better visible in medical imaging procedures (e.g. radiography, magnetic resonance imaging, sonography) are also medicinal products.
This legal definition is laid down among others in Section 2 sub-section 1 of the Medicinal Products Act ("Arzneimittelgesetz", AMG) which has been in force since 1978. This Section specifies that the provisions of the Medicinal Products Act, the main purpose of which is the assurance of drug safety, apply to the products mentioned therein. Furthermore, Section 3 AMG lists the substances that are specific for the manufacture of a medicinal product. These definitions are adapted to the terminology of Directives 2001/83/EC and 2001/82/EC and allow a distinction from other products like foodstuffs (including dietary supplements), cosmetics or medical devices.