If you seek medical treatment in the United States, it is your responsibility to pay for the services.   Purchasing medical insurance can offset the risk of having to pay high medical bills if you happen to need treatment during your visit to the U.S.   One company that offers medical insurance for visitors to the U.S. is:

Gateway Visit America

Call 1-800-282-4495 or visit http://www.gatewayplans.com/gw_vis.cfm

You must enroll within 7 days of arrival in the United States; proof of arrival date may be required.

When purchasing a medical insurance policy, be sure to review the types of coverage the plan offers.  For example, some policies will not cover accidents from sports activities such as skiing or boating.