The hurdle to getting an income-tax deduction for medical expenses is high: 7.5% of adjusted gross income (10% if the taxpayer owes alternative minimum tax). But many taxpayers don't know that the list of what qualifies is far broader than what insurance typically reimburses. If one single or many combined expenses are high, the deduction could be significant.

Here, according to J.K. Lasser tax expert Barbara Weltman, are 10 deductible medical expenses many people overlook—plus five the Internal Revenue Service prohibits....