An official definition of the term is defined in section 3 (3) GCP ordinance: Investigational medicinal products are dosage forms of active substances or placebos that are tested in a human clinical trial or used as comparative medicinal products or used to produce certain reactions in humans. This includes medicinal products that are not approved and approved medicinal products if they are used in a clinical trial in humans in a different pharmaceutical form or for an unauthorized application or to obtain additional information about the authorized medicinal product.