At the EU social security coordination site, it´s possible to find information about this card.
The card is free and gives access to medically necessary, state-provided healthcare during a temporary stay in any of the 28 EU countries, Iceland, Lichtenstein, Norway and Switzerland, under the same conditions and at the same cost (free in some countries) as people insured in that country.
If you unexpectedly need treatment while travelling in an EEA Member State or Switzerland, your European Health Insurance Card ensures that the cost of your treatment is covered.
This card can be a major support if an accident or some medical issue happens while travelling.
Cards are issued by the national health insurance provider of each country. To know what steps are needed to get this card, please check this link.
In Portugal, the card can be requested at Segurança Social.
We four have this card and this is Clara´s card: