Boxed Warning
Also known as: Black Box Warning, Black-Box Warning, BBW
Verified from eCFR 21 CFR 201.57 on 06-02-2026A boxed warning is a labeling requirement reserved for the most serious risks identified for a prescription drug, displayed in a box at the top of the FDA-approved label so it stands out from other safety information. It is generally based on clinical data, though serious animal toxicity findings can also support one when clinical data are not available. The federal regulation defining how a boxed warning must be formatted and what it must contain is quoted in full below.
MedivaScan summary. The authoritative source quote follows below.eCFR 21 CFR 201.57 definition
Boxed warning. Certain contraindications or serious warnings, particularly those that may lead to death or serious injury, may be required by the FDA to be presented in a box. The boxed warning ordinarily must be based on clinical data, but serious animal toxicity may also be the basis of a boxed warning in the absence of clinical data. The box must contain, in uppercase letters, a heading inside the box that includes the word “WARNING” and conveys the general focus of the information in the box. The box must briefly explain the risk and refer to more detailed information in the “Contraindications” or “Warnings and Precautions” section, accompanied by the identifying number for the section or subsection containing the detailed information.