[Code of Federal Regulations] [Title 21 Volume 5] [Revised as of April 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR338.3] [Page 226] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PART 338--NIGHTTIME SLEEP-AID DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE--Table of Contents Subpart A--General Provisions Sec. 338.3 Definition. As used in this part: Nighttime sleep-aid. A drug that is useful for the relief of occasional sleeplessness by individuals who have difficulty falling asleep.