The Swiss authorities online
If you unexpectedly fall ill during a short stay abroad, your health insurance company will pay for any emergency treatment you require. It does not cover the cost of any treatment you may choose to have when abroad or any medicines you decide to buy.
If you do not get ill while abroad, but your doctor sends you to another country for treatment that is not available in Switzerland, you should find out in advance from your health insurer if this treatment is covered.
The level of coverage for emergencies varies from country to country. In EU- / EFTA countries the European Health Insurance Card (EHIC), which you will have received from your health insurer, entitles you to the same paid services as someone who is insured in the respective country. So always take your EHIC with you when travelling in the EU or an EFTA state.
In non-EU / EFTA countries you can recover the costs of medical emergency treatment, but only up to a maximum of twice what the same treatment would have cost in Switzerland. If you require higher coverage, you need to take out additional insurance.
In some non-EU / EFTA countries it may be advisable to take out additional insurance to cover the cost of treatment abroad. For example, in the USA and Canada health costs are high and treatment can soon cost more than twice what it would in Switzerland, in which case it is no longer covered by your usual health insurance policy.