If you need medical treatment during travels in the EU, Norway, Iceland, Liechtenstein (EEA), or Switzerland you will have to use the Blue European Health Insurance Card.
The Blue European Health Insurance Card is a free card that gives you access to medically necessary, state-provided healthcare during a temporary stay in any of the 27 EU countries, EEA (Iceland, Liechtenstein and Norway), Switzerland and the United Kingdom.
The card is valid for five years. The validity can however be shorter, if you are planning on using the card for purposes other than holiday or living abroad. It is important that your card is valid for the entire period abroad.
The Blue Health Insurance Card does not give you access to the public health care in countries that are not mentioned above. If you wish to have a health insurance, while staying in in one of these countries, then you should take out a travel insurance with your private insurance provider.