HSAs are IRAs on Steroids

A Health Savings Account, or HSA, is a financial account established by an individual or family to pay for qualified medical expenses.
U.S. federal regulations require citizens to have a minimum deductible on their health insurance from all sources in order to make tax-deductible contributions to their Health Savings Accounts (HSA).
HSAs combine the benefits of both traditional and Roth 401(k)s and IRAs for medical expenses. Taxpayers receive a 100% income tax deduction on annual contributions, they may withdraw HSA funds tax-free to reimburse themselves for qualified medical expenses, and they may defer taking such reimbursements indefinitely without penalties.
HSAs are unique—“IRAs on Steroids”—with triple tax advantages:

1. Tax-deductible contributions,
2. Tax-free accumulation of interest and dividends tax-free, and
3. Tax-free distributions for qualified medical expenses.

http://www.zanebenefits.com/blog/bid/143070/Health-Savings-Account-HSA-2013-Rules-Requirements