‘Adverse event’ means any untoward medical occurrence in a subject to whom a medicinal product is administered and which does not necessarily have a causal relationship with this treatment. EU 536/2014 Art. 2 Abs. 2 (32)

In the context of pharmacovigilance and outside a clinical trial: Any untoward medical occurrence in a patient to whom a medicinal product is administered and which does not necessarily have a causal relationship with this treatment (based on ICH-E2D Guideline, see GVP Annex IV). An adverse event can therefore be any unfavourable and unintended sign (e.g. an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to this medicinal product (see GVP Annex IV, ICH-E2D Guideline). GVP Annex I - Definitions (Rev 5)

‘Adverse event’ means any untoward medical occurrence, unintended disease or injury or any untoward clinical signs, including an abnormal laboratory finding, in subjects, users or other persons, in the context of a clinical investigation, whether or not related to the investigational device. MDR Art. 2 (57)