Which item is NOT required on a drug label?

The correct answer, which indicates the item not required on a drug label, is the tax identification number. While various regulatory bodies have established guidelines on drug labeling, essential elements typically include an expiration date, the manufacturer's name and address, and a control or lot number. These components ensure that the drug can be tracked for safety, quality, and regulatory compliance.

The expiration date is crucial for ensuring that the drug is effective and safe for use until that time. The manufacturer's name and address provide accountability and traceability in case of recalls or adverse effects. The control or lot number is necessary for identifying specific batches of products, which is important for quality control and tracking any potential issues with particular production runs.

In contrast, a tax identification number is generally relevant for financial purposes, such as taxation and accounting, but does not play a direct role in the safety, effectiveness, or regulatory compliance of the pharmaceutical product itself. Consequently, it is not a mandated part of a drug label.