FDA Warning Letters

FDA Warning Letters

The Significance of Warning Letters

FDA Waring Letters are the most commonly used enforcement tool. Employed across product categories FDA Warning Letters are common food, dietary supplements, cosmetics, drugs, medical devices, biologics (including clinical and pre-clinical research), veterinary medicine (food, supplements, drugs), and tobacco products (cigarettes and e-cigarettes).

The FDA views Warning Letters as serving two purposes. First it creates a record of the violation. This is known as “prior notice.” An accumulation of Warning Letters for the same or similar violations allows the Agency to quickly escalate the penalties imposed, including criminal prosecution. Second, the Warning Letter is a “non-final” recommendation intended to change a recipient company’s behavior. This is a bit misleading since Warning Letters are intended to impose changes beyond simple recommendations. The effect, however, is an non-judicially-contestable enforcement action. Hence the severity and importance.

Warning Letters are often used following facility inspections and Form 483. Form 483 is a list of Inspectional Observations. In short a list of violations found during an inspection. In some cases the violations are routine, but the response indicates a wider compliance problem leading the FDA to issue a Warning Letter. In other cases, the violations are too severe for a Form 483 which is not reviewed by Compliance or Center Directors prior to issuance. The Regulatory Procedures Manual includes a list of violations deemed inappropriate for a Form 483. Common Warning Letter topics include:

  • Unapproved medical devices;
  • OTC Drug Monograph deviations (claims, ingredients, indications for use);
  • Unapproved veterinary drugs (often foods with therapeutic claims);
  • Violations of Good Manufacturing Practices (GMPs or cGMPs);
  • Violations of Good Laboratory Practices (GLPs);
  • Unapproved dietary supplements;
  • Unapproved food additives;
  • Unapproved color additives;
  • Violations of
    Share this:
Marc Sanchez

Marc Sanchez

Marc is dedicated to helping his clients navigate the complex world of FDA and USDA legislation. He represents FDA-regulated companies in the food, dietary supplement, beverage, cosmetic, medical device, and drug industries.

Marc is the author of two textbooks and a lecturer at Northeastern University. He is a member of the Washington State Bar Association and the D.C. Bar Association.


  1. Redacting a FOIA Request - FDA Atty on April 1, 2020 at 2:13 pm

    […] submissions (e.g., NDAs, 510(k)s, PMTA, etc.) and enforcement materials and correspondence (e.g., Warning Letter responses, Form 483s, It Has Come to Our Attention (IHCTOA) letters, etc.). Redacting a FOIA request means […]

Leave a Comment

You must be logged in to post a comment.

Are you in trouble with the FDA?

Don’t panic — you’ve got backup. Download 5 Tips to Help You Navigate FDA Enforcement and learn how to resolve the situation right now.

Expert knowledge of FDA regulations that helps you strategically grow your business