This is any health care service that your health insurance plan does not pay for or cover.  With excluded services, you will generally pay 100% of the cost unless the service is considered medically necessary.

For example, plastic surgery is almost always on a providers exclusion list. If a plan holder wants an alteration, they will generally be required to pay for it themselves. However, if the procedure is meant to address functional impairments or to repaird damage caused by infection or disease, the plan may make an exceptions and pay for the procedure after normal cost sharing.