It also told the British government that it wants to retain its ability to decide what care it will pay for.
Currently, EU citizens get reimbursed for urgent treatment anywhere in the 27-nation bloc on condition they contribute to a health insurance scheme at home.
For non-urgent medical care, they are free to shop around, but first need the green light from their insurer.
Under the overhaul of guidelines from the 1970s, citizens would be able to seek non-urgent treatment, such as hip replacement or teeth whitening, if covered by insurance, anywhere and at any time, but would have to pay up front.
Their insurer would then reimburse them as if the treatment were carried out at home.
"As long as the treatment is covered under their national health care system ... patients will be reimbursed up to the level of the same or similar
treatment at home," said Androulla Vassiliou, the EU health commissioner.
Should the treatment involve a longer hospital stay, the insurer would still get the right to authorise the treatment in advance, according to the draft rules, which still need to be approved by EU governments and the European parliament before coming into force.
Wednesday's proposal follows several landmark rulings by the European court of justice, which said patients have the right to seek health care anywhere in the EU and get reimbursed at home.
There are considerable differences between the cost of various medical operations within the EU, and the new system would be especially advantageous for citizens of rich countries seeking treatment in states where health care is cheaper.
Total health care expenditure in the EU is $1.6 trillion annually, out of which only $16 billion is spent on patients treated in a country other than their own.