If you itemize your tax return rather than take the standard deduction, the cost of medical expenses -- including vitamins you purchase for yourself, your spouse and all of your dependents -- are tax deductible on Schedule A if you meet certain criteria. It all depends on whether the vitamins are used for their general health benefits or to alleviate or prevent a mental or physical illness.
Vitamins for General Health Benefits
Most of the vitamins you purchase that promote various health benefits can't be included in the cost in your deductible medical expenses. To be deductible, all medical expenses must primarily relate to the prevention and alleviation of an illness, whether it be mental or physical in nature.
Vitamins to Treat Medical Condition
The only time the cost of vitamins is deductible is when directed by a medical professional. However, the vitamins must be used to treat a specific illness that has been diagnosed by a physician. Even if your annual vitamin cost is deductible, only the portion of your total medical expenses that exceed 10 percent of your adjusted gross income, or 7.5 percent if you or your spouse is 65 or older, is what you can actually deduct. This applies to all medical costs, including vitamin purchases.