An NDC registered over-the-counter health product refers to an over-the-counter medication or health product that has been assigned a unique National Drug Code by the U.S. Food and Drug Administration (FDA). The NDC is a 10-digit, three-segment number that identifies the product's manufacturer, the product itself, and the package size. This code is crucial for tracking and identifying specific products, ensuring accurate labeling, and assisting in the reporting and monitoring of adverse events associated with the product.