CFR › Title 21 › Part 338Part 338 — Nighttime Sleep-Aid Drug Products for Over-the-Counter Human UseSubpart A — General Provisions§ 338.1— Scope.§ 338.3— Definition.Subpart B — Active Ingredients§ 338.10— Nighttime sleep-aid active ingredients.Subpart C — Labeling§ 338.50— Labeling of nighttime sleep-aid drug products.