European Health Insurance Card

The European Health Insurance Card (EHIC) is issued free of charge to anyone who is insured by or covered by a statutory social security scheme of the EEA countries or Switzerland and certain citizens and residents of the United Kingdom. It allows holders to receive medical treatment in another member state in the same way as residents of that state—i.e., free or at a reduced cost—if treatment becomes necessary during their visit (for example, due to illness or an accident), or if they have a chronic pre-existing condition which requires care such as kidney dialysis.

Source: Wikipedia — European Health Insurance Card (CC BY-SA 4.0)