Food composition databases are critical to assess and plan dietary intakes. Dietary supplement databases are also needed because dietary supplements make significant contributions to total nutrient intakes. However, no uniform system exists for classifying dietary supplement products and indexing their ingredients in such databases. Differing approaches to classifying these products make it difficult to retrieve or link information effectively. A consistent approach to classifying information within food composition databases led to the development of LanguaL™, a structured vocabulary. LanguaL™ is being adapted as an interface tool for classifying and retrieving product information in dietary supplement databases. This paper outlines proposed changes to the LanguaL™ thesaurus for indexing dietary supplement products and ingredients in databases. The choice of 12 of the original 14 LanguaL™ facets pertinent to dietary supplements, modifications to their scopes, and applications are described. The 12 chosen facets are: Product Type; Source; Part of Source; Physical State, Shape or Form; Ingredients; Preservation Method, Packing Medium, Container or Wrapping; Contact Surface; Consumer Group/Dietary Use/Label Claim; Geographic Places and Regions; and Adjunct Characteristics of food.