In general, eligible expenses include medical, prescription drug, dental and vision expenses that you pay out of pocket, such as deductibles, co-insurance and co-pays. Besides those common expenses, eligible expenses also include premiums for certain qualified long-term care insurance or COBRA coverage. You can also use it to pay Medicare premiums or other health insurance (but not premiums for a Medicare supplement policy). A full list of these expenses is described in IRS Publication 502.