Zurich University Hospital has stopped treating North American "medical tourists", fearing million-dollar claims from litigious patients if operations go wrong.
Hospitals in canton Valais have also adopted measures to protect themselves against visitors from the United States, Canada and Britain.
"The directive applies only to patients from [the US and Canada] who come to Zurich for elective [non-essential] health treatments," Zurich University Hospital spokeswoman Petra Seeburger told swissinfo.ch.
"It is not because treatment is not financed; it is because of different legal systems."
In a statement the hospital said it was "not prepared to risk astronomical damages or a massive increase in premiums".
Seeburger emphasised that the restrictions only affected people not domiciled in Switzerland.
"Of the 170,000 patients Zurich University hospital treats annually, about 3,000 come from abroad and 30 are North Americans. These are mainly emergencies and would of course continue to be treated," she said.
"Most patients choosing the Zurich University Hospital come from countries near Switzerland, the Middle East or Russia."
In the southern canton of Valais medical tourists have to sign a "specific consent form" which states that the limits of responsibility are fixed in Swiss civil law.
Bernard Gruson from Geneva University Hospital says all patients have to sign a consent form, whether they are foreign or not.
Other Swiss hospitals aren't so risk averse.
"As long as a patient is sufficiently insured or has paid a deposit, we'll treat them," was the response from university hospitals in Bern and Basel.
"We have a good liability insurance – including for foreign claims," said Andreas Bitterlin from Basel University Hospital, which last year treated around a hundred North Americans as inpatients.
Health tourism pioneer
Switzerland has a long history of medical tourism, dating back to the 19th century when wealthy travellers came to "take the waters".
In the early days healing mineral waters and fresh alpine air promised miracle cures for all kinds of diseases, notably tuberculosis.
Nowadays, private Swiss clinics advertise surgery in in-flight magazines while agencies specialising in organising medical treatment for foreigners offer a deluxe service covering everything from interpreters to visas.
People travel to Switzerland for a broad range of treatments and procedures, plastic surgery included. One well publicised patient was Italian Prime Minister Silvio Berlusconi who came to Switzerland for an eye operation two years ago. The late Saudi King Fahd also underwent medical treatment in Switzerland.
The health tourism sector is estimated to be worth SFr900 million ($870 million) a year as Switzerland's reputation for healthcare excellence holds firm.
Nevertheless, experts believe Switzerland could still do more to attract wealthy foreigners looking for top class treatment.
A study on Switzerland's potential in the area, carried out by Zurich-based think tank the Gottlieb Duttweiler Institute, highlighted complex cases requiring specialist treatment. Discreet Switzerland could also offer privacy to VIPs, it said.
A forecast by Deloitte Consulting published in August 2008 projected that medical tourism originating in the US could jump by a factor of ten over the next decade. An estimated 750,000 Americans went abroad for health care in 2007.
The growth in medical tourism has the potential to cost US healthcare providers billions of dollars in lost revenue, it said.
Thomas Stephens, swissinfo.ch
Approximately 11% of Swiss gross domestic product is spent on the public health care system. The average for OECD countries is 8.8%. (All 2005 figures.)
Total expenditure of health per capita is around $4,000.
There are 321 hospitals in Switzerland (2007). 68% are public, 38% are private. The average stay is 10.9 days.
Cases treated in 2007: hospitals 1.15 million, psychiatric clinics 107,000 and special clinics 209,000.
Source: World Health Statistics 2008, Federal Statistics Office, Swiss Hospital Association
The Swiss health tourism market can be divided into two sectors: medical and wellness.
Up to 30,000 foreigners a year are treated in Swiss hospitals with a further 150,000 travelling here for health spa holidays.
Patients who travel to Switzerland for medical treatment often have other non-medical reasons for choosing the country.
The Swiss healthcare system enjoys an excellent reputation. Word of mouth remains very important for new referrals.