The U.S. Food and Drug Administration (FDA) has published guidance titled “Draft Guidance for Industry: Dietary Supplements: New Dietary Ingredient Notifications and Related Issues” that aims to clarify when premarket safety notifications for dietary supplements containing new dietary ingredients (NDI) are necessary and how to prepare premarket safety notifications (NDI notifications). Arranged in a question-and-answer format, the guidance covers the following topics: (i) what qualifies as an NDI; (ii) when an NDI notification is necessary; (iii) the procedures for submitting an NDI notification; (iv) the types of data and information that FDA recommends manufacturers and distributors consider when evaluating the safety of a dietary supplement containing an NDI; and (v) what should be included in an NDI notification. It also clarifies the definition of a dietary supplement, which affects whether a particular substance may be marketed as a dietary ingredient in a supplement.