Are Toothbrushes FSA Eligible? IRS Rules and the LMN Exception

Are toothbrushes FSA eligible? In almost every case, no. The IRS classifies a standard manual or electric toothbrush as a personal-use item rather than a medical expense, and FSA plans follow that classification.¹ The one way around the rule is a Letter of Medical Necessity from a dentist or physician that ties the toothbrush to a diagnosed condition. Without that letter, the purchase won’t be reimbursed, no matter where you buy it.

Why the IRS Says No

The IRS draws a hard line between items that treat a specific condition and items you’d use for general health anyway. A toothbrush falls on the general-health side. IRS Publication 502 actually uses toothbrushes and toothpaste as its example of a nondeductible personal expense.¹ The reasoning: everyone brushes their teeth whether they have a dental condition or not, so the cost is personal upkeep.

The same logic knocks out regular toothpaste, basic floss, and standard replacement heads for electric brushes. None of these treat a diagnosed disease on their own, so none of them pass the IRS test. This catches people off guard, especially when they see other oral-care products stocked at FSA-eligible retailers.

The Letter of Medical Necessity Exception

If a dentist or physician determines that a specific toothbrush is needed to treat a diagnosed condition, a Letter of Medical Necessity turns the purchase into a qualified medical expense. Dentists most commonly write these for patients recovering from oral surgery, managing severe gum disease, or dealing with a condition that makes standard brushing ineffective or harmful.

The letter needs three things: the diagnosis, the specific product being recommended, and an explanation of why it’s necessary for treatment rather than general hygiene. A vague note saying “patient should use an electric toothbrush” won’t be accepted. FSA administrators reject letters that don’t tie the product to a specific medical condition, and the letter has to make clear the item isn’t being recommended for cosmetic purposes or general wellness.

Electric toothbrushes are the most common candidates, and some manufacturers provide template letters for dentists because the scenario comes up often enough. Water flossers work the same way: not eligible on their own, eligible with a Letter of Medical Necessity and a detailed receipt.²

Keep a copy of the letter with your tax records. Your FSA administrator may request it when you submit a claim, and some plans require you to renew the letter each plan year for ongoing purchases.

Dental Expenses That Qualify Without a Letter

Plenty of dental expenses qualify on their own because their medical purpose is inherent. You don’t need any special documentation beyond a receipt.¹

Orthodontic treatment, including braces, retainers, and clear aligners, because they correct structural problems with teeth or jaw.
Restorative work such as fillings, crowns, bridges, and dentures.
Dental implants when they replace missing teeth or prevent bone loss from a medical condition, though not when placed purely for cosmetic reasons.
Diagnostic services including X-rays, professional exams, and routine cleanings.
Surgical procedures like extractions, root canals, and periodontal surgery, including copayments and deductibles.
Mouthguards prescribed for teeth grinding or jaw disorders.

Hold onto your receipts and any explanation-of-benefits statements from your dental insurance in case your administrator asks for documentation later.

Over-the-Counter Dental Products

The CARES Act made OTC medicines FSA eligible without a prescription starting in 2020.³ That opened up several dental products that were previously harder to reimburse.

Toothache pain relievers, teething gels, and canker sore treatments all qualify as OTC medicines. Medicated mouth rinses with active drug ingredients qualify too. These products treat a specific symptom or condition, which puts them on the right side of the IRS line.

What the CARES Act did not change is the status of general-health items that aren’t medicines. Your toothbrush, regular toothpaste, and standard floss still don’t qualify, because they aren’t classified as drugs. A toothache gel from the same pharmacy aisle as your toothpaste is eligible; the toothpaste next to it is not.

Cosmetic Dental Work Is Excluded

Any dental procedure aimed at improving appearance rather than treating a condition is excluded from FSA reimbursement. Teeth whitening is the clearest example, and the IRS names it directly as ineligible.¹ Cosmetic veneers and elective reshaping fall into the same category.

There is an exception for cosmetic work that corrects a deformity caused by a birth defect, an accident, or a disfiguring disease. Reconstructive dental surgery after a car accident or as part of cancer treatment is fully eligible.¹ The distinction is whether the procedure restores function or treats a medical consequence rather than simply improving appearance.

Paying With FSA Funds and Keeping Records

You have two ways to use FSA funds for eligible dental expenses. The first is your FSA debit card, which works at retailers and dental offices whose systems automatically verify eligible items at checkout. When the merchant’s system flags a purchase as qualified, the transaction goes through and no additional paperwork is usually needed.

The second option is paying out of pocket and filing for reimbursement. Submit a claim form to your FSA administrator with an itemized receipt showing what you bought, the date, and the cost. For expenses that required a Letter of Medical Necessity, attach a copy of the letter. The administrator matches the receipt against the letter before approving payment.

Either way, keep your documentation organized. FSA administrators can audit past transactions and request receipts even for debit card purchases. If you can’t produce the documentation, the administrator may deny the expense after the fact, and the amount could be treated as taxable income.⁴

So the practical answer, if you’ve been eyeing that electric brush: talk to your dentist first. If there’s a diagnosed reason you need it, ask for the letter in writing with the diagnosis, the product, and the clinical rationale spelled out. If there isn’t, the toothbrush comes out of your regular budget, and your FSA dollars go toward the cleanings, fillings, and prescriptions that qualify without a fight.

1
Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses
2
FSAFEDS. Eligible Health Care FSA (HC FSA) Expenses
3
FSAFEDS. FAQs – All Over-the-Counter (OTC) Medicines or Drugs
4
Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans