Title 21 of the Code of Federal Regulations

Title 21 is the portion of the Code of Federal Regulations that governs food and drugs within the United States for the Food and Drug Administration (FDA), the Drug Enforcement Administration (DEA), and the Office of National Drug Control Policy (ONDCP). It is divided into three chapters: Chapter I — Food and Drug Administration Chapter II — Drug Enforcement Administration Chapter III — Office of National Drug Control Policy == Chapter I == Most of the Chapter I regulations are based on the Federal Food, Drug, and Cosmetic Act.

Source: Wikipedia — Title 21 of the Code of Federal Regulations (CC BY-SA 4.0)