Publication 502

Publication 502 is the IRS booklet on medical and dental expenses for Schedule A. It is the plain-language version of the rules in IRC § 213 and is the document a CPA or tax professional reaches for first when a medical-expense question shows up.

Publication 502 does not name celiac specifically. The booklet is a category list (acupuncture, ambulance, artificial limbs, and so on alphabetically) plus a set of general rules at the front. The general rule that matters for the gluten-free premium is the rule on special diets prescribed to treat a medical condition. Plain language: when a diet is the medically prescribed treatment for a medical condition, the extra cost of that diet over what an ordinary diet would have cost is a medical expense.

That general rule, plus Revenue Ruling 55-261 (the 1955 IRS ruling that established the special-diet rule) and IRS Information Letter 2011-0035 (the most direct modern IRS letter on gluten-free costs and celiac), is the substantiation chain a CPA or tax professional puts together when a celiac household includes a gluten-free premium on Schedule A.

What Publication 502 does not say is also worth naming. It does not give a per-item dollar value. It does not publish a household-average lookup table. It does not address restaurants or travel meals with the clarity it addresses grocery items. It does not address whether the Gluten Hero year-end report itself is acceptable substantiation, which is a separate professional-judgment call.

For the full walkthrough, with quotes from the booklet and the underlying ruling, read What Publication 502 actually says about celiac.