OBJECTIVES:   A medical food is formulated to be consumed or administered enterally under the supervision of a physician, and is intended for the specific dietary management of a disease or condition for which distinctive nutritional requirements are established by medical evaluation. In the US, medical foods are a special product category regulated by the FDA. In Europe, a similar category called “Foods for Special Medical Purposes” (FSMPs) is covered by the Foods for Particular Nutritional Uses directive and regulated by the European Commission (EC). Our objective is to review and compare the characteristics of, and regulatory environments for, medical foods and FSMPs. METHODS:   We conducted internet and PubMed searches to identify information and guidance covering medical foods and FSMPs, including relevant FDA and EC regulations. We also reviewed and compared the characteristics, place in therapy, and potential economic impact of these products. RESULTS:   Medical foods do not require pre-approval from the FDA for marketing. Unlike nutritional supplements, which have no disease claim and are intended for healthy individuals, medical foods must make a disease claim and are intended for use in specific diseased populations. Disease claims must be supported by sound scientific evidence substantiating claims of successful nutritional management of the disease. All ingredients must be approved food additives or classified as Generally Recognized as Safe (GRAS). Reimbursement for medical foods is inconsistent, and varies by product and by health plan. Like medical foods in the US, FSMPs are intended for use only under medical supervision, but they must comply with EC regulations. There has been little to no economic research conducted with products in these categories. CONCLUSIONS:   Medical foods and FSMPs can play a key role in the nutritional and metabolic support of patients with certain diseases and conditions, although their economic impact has not been studied.