Culture File 40:
There is no national health plan in the U.S.A. so private medical insurance is essential for visitors. If you don’t have insurance, you could be refused admission to a hospital (unless your problem is very serious).
You will have to pay even in a public hospital. Even with a simple illness, you may have more tests than in your own country because American doctors can have legal problems if they have not checked every possibility.
In the U.S.A., Canada, the U.K. and Australia, many medicines (e.g. antibiotics) must be prescribed by a doctor. You cannot simply buy them at a pharmacy.