BRUSSELS – When Ludwig Leichtle headed from his home in Salgen, Germany, to an Italian spa town for a healing soak recommended by his doctor, he figured his employer, Germany’s national labor office, would foot the bill.

Thermal cures commonly are included in German health plans, and the civil servant felt he should be able to take his taxpayer-financed bath wherever he wanted.

The European Court of Justice agreed. When the labor office refused to pay, Mr. Leichtle filed suit and won. He was reimbursed in September – including his travel expenses to Italy.

Mr. Leichtle’s right to a cure in the European Union country of his choice is unnerving national health-care providers and insurers across Europe, exposing a contradiction between two of the E.U.’s bedrock principles: One mandates services should have no national borders within the E.U.; the other says national governments deliver and organize health care for their own citizens. E.U. efforts to legislate a single market for services have a long way to go, and health care is a major source of delay. At a recent hearing on a proposal to remove service-market barriers, most of the debate centered on implications for the health sector – namely whether the measure would infringe countries’ lawful right to organize their own systems. But one European Commission spokesman said the proposal merely reflects judgments already made by Europe’s high court, and health-care experts warned against exempting the sector from market rules.

“It’s high time we take a consumer perspective on health care. Otherwise, there is a large risk that national health-care systems will lose credibility and support,” said Johan Hjertqvist of Swedish health-policy think tank Timbro Halsa, addressing the European Parliament. Mr. Hjertqvist cited a recent survey of 8,000 Europeans in which two-thirds said they would go abroad for health care if it was possible to use their national funding.

Resolving the issue may take years. In a bloc with 25 different health-care systems and pricing schemes, countries fear that allowing people to shop around for health services could be messy – or worse. “You can’t classify health-care services as ordinary economic services: They are supported by public budgets, and each country has its own sensitive balance,” said a spokesman for the Belgian health ministry.