Most hospitals can help you at the casualty department (EHBO) without a reference note from a general practitioner. For the majority of other departments you are obliged to obtain a prescription (for example from a general practitioner).
You can get emergency help 24 hours a day. Ask for the EHBO-post (pronounce: ā-ha-bā-o). If there is an emergency or a life-threatening situation, you can always call 112, the emergency number. They can assist you with, for example, police, firemen and doctors.
When you go to the hospital, always take your insurance papers with you.
Hospitals in Rotterdam
Tel: 010 704 07 04
Havenziekenhuis (also Travel Clinic)
Tel: 010 404 33 00
Sint Franciscus Gasthuis
Tel: 010 461 61 61
Tel: 010 258 50 00
Tel: 010 291 19 11
Tel: 010 297 50 00