By Jason Watson (Google+)
You can. In two scenarios.
First, if you are self-employed there are provisions allowing you to deduct the cost of health insurance premiums.
Second, if your health insurance premiums are paid out-of-pocket as an after-tax expenses. Typically most taxpayers are paying for health insurance through a qualified plan (aka Section 125 or Cafeteria Plan) and their premiums are deducted pre-tax. Therefore you are already receiving an instant tax deduction for health insurance. To count it again would be double-dipping, and is frowned upon by the IRS.