A multivitamin is a preparation intended to be a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, and injectable formulations. Other than injectable formulations, which are only available and administered under medical supervision, multivitamins are recognized by the Codex Alimentarius Commission (the United Nations' authority on food standards) as a category of food.
Multivitamin supplements are commonly provided in combination with dietary minerals. A multivitamin/mineral supplement is defined in the United States as a supplement containing 3 or more vitamins and minerals that does not include herbs, hormones, or drugs, where each vitamin and mineral is included at a dose below the tolerable upper level, as determined by the Food and Drug Board, and does not present a risk of adverse health effects. The terms multivitamin and multimineral are often used interchangeably. There is no scientific definition for either.
In otherwise healthy people, most scientific evidence indicates that multivitamin supplements do not prevent cancer, heart disease, or other ailments, and regular supplementation is not necessary. However, there may be specific groups of people who may benefit from multivitamin supplements (for example, people with poor nutrition or at high risk of macular degeneration).