Message Board

Jul 7, 2026

Letters of Medical Necessity (LMNs) and Eligible Expenses

Some health care expenses, such as general health and wellness items, may be eligible for reimbursement only if the expense qualifies as an eligible expense and a doctor or other licensed health care practitioner, acting within the scope of their license, certifies that they are medically necessary. These dual-purpose expenses require a Letter of Medical Necessity (LMN) (PDF) to be eligible for reimbursement; examples include vitamins, homeopathic remedies, and air purifiers. The LMN must indicate a specific medical condition being treated, the recommended treatment, the duration of treatment, and include the health care practitioner's signature.

Understanding what expenses may be eligible with an LMN can be confusing. Over the last few years, certain companies have misrepresented the circumstances in which certain food and wellness expenses are eligible for reimbursement from Health Care FSAs. In response, the Internal Revenue Service issued an alert in 2024 to remind FSA participants and plan administrators that personal expenses for general health and wellness are not considered medical expenses under US tax law, which regulates FSAs. These companies offer notes from doctors and other health care practitioners based on self-reported information for a fee and mistakenly claim that such documentation can convert the item to a medical expense. However, this documentation does not make such an expense reimbursable. To be reimbursable, dual-purpose items require a properly completed LMN and a detailed receipt.

You may refer to our lists of eligible expenses for the most common types of eligible expenses. Any expenses that are listed as potentially eligible may require additional documentation such as an LMN.