21 U.S.C. § 207 - U.S. Code - Unannotated Title 21. Food and Drugs § 207. Restrictions on sales;  written orders or prescriptions

It shall be unlawful for any person, firm, or corporation whose permanent allegiance is due to the United States, either personally or by servant or agent or as the servant or agent of any other person or of any firm or corporation, to sell, furnish, or give away any cocaine, salts of cocaine, or preparation containing cocaine or salts of cocaine, or morphine or preparation containing morphine or salts of morphine, or any opium or preparation containing opium, or any chloral hydrate or preparation containing chloral hydrate, except upon the original written order or prescription of a recognized and reputable practitioner of medicine, dentistry, or veterinary medicine, which order or prescription shall be dated and shall contain the name of the person for whom prescribed, or, if ordered by a practitioner of veterinary medicine, shall state the kind of animal for which ordered and shall be signed by the person giving the order or prescription.  Such order or prescription shall be, for a period of three years, retained on file by the person, firm, or corporation who compounds or dispenses the article ordered or prescribed, and it shall not be compounded or dispensed after the first time except upon the written order of the original prescriber.