21 U.S.C. § 209
It shall be unlawful for any person, firm, or corporation whose permanent allegiance is due to the United States to sell or deliver to any other person any of the following-described substances, or any poisonous compound, combination, or preparation thereof, to wit: The compounds of and salts of antimony, arsenic, barium, chromium, copper, gold, lead, mercury, silver, and zinc, the caustic hydrates of sodium and potassium, solution or water of ammonia, methyl alcohol, paregoric, the concentrated mineral acids, oxalic and hydrocyanic acids and their salts, yellow phosphorus, Paris green, carbolic acid, the essential oils of almonds, pennyroyal, tansy, rue, and savin; croton oil, creosote, chloroform, cantharides, or aconite, belladonna, bitter almonds, colchicum, cotton root, cocculus indicus, conium, cannabis indica, digitalis, ergot, hyoscyamus, ignatia, lobelia, nux vomica, physostigma, phytolacca, strophanthus, stramonium, veratrum viride, or any of the poisonous alkaloids or alkaloidal salts derived from the foregoing, or any other poisonous alkaloids or their salts, or any other virulent poison, except in the manner following, and, moreover, if the applicant be less than eighteen years of age, except upon the written order of a person known or believed to be an adult.
It shall first be learned, by due inquiry, that the person to whom delivery is about to be made is aware of the poisonous character of the substance and that it is desired for a lawful purpose, and the box, bottle, or other package shall be plainly labeled with the name of the substance, the word "Poison", the name of at least one suitable antidote, when practicable, and the name and address of the person, firm, or corporation dispensing the substance. And before delivery be made of any of the foregoing substances, excepting solution or water of ammonia and sulphate of copper, there shall be recorded in a book kept for that purpose the name of the article, the quantity delivered, the purpose for which it is to be used, the date of delivery, the name and address of the person for whom it is procured, and the name of the individual personally dispensing the same; and said book shall be preserved by the owner thereof for at least three years after the date of the last entry therein. The foregoing provisions shall not apply to articles dispensed upon the order of persons believed by the dispenser to be recognized and reputable practitioners of medicine, dentistry, or veterinary surgery. When a physician writes upon his prescription a request that it be marked or labeled "Poison" the pharmacist shall, in the case of liquids, place the same in a colored glass, roughened bottle, of the kind commonly known in trade as a "poison bottle", and, in the case of dry substances, he shall place a poison label upon the container. The record of sale and delivery above mentioned shall not be required of manufacturers and wholesalers who shall sell any of the foregoing substances at wholesale to licensed pharmacists, but the box, bottle, or other package containing such substance, when sold at wholesale, shall be properly labeled with the name of the substance, the word "Poison," and the name and address of the manufacturer or wholesaler. It shall not be necessary, in sales either at wholesale or at retail, to place a poison label upon, nor to record the delivery of, the sulphide of antimony, or the oxide or carbonate of zinc, or of colors ground in oil and intended for use as paints, or calomel; nor in the case of preparations containing any of the substances named in this section, when a single box, bottle, or other package, or when the bulk of one-half fluid ounce or the weight of one-half avoirdupois ounce does not contain more than an adult medicinal dose of such substance; nor in the case of liniments or ointments sold in good faith as such, when plainly labeled "For external use only"; nor, in the case of preparations put up and sold in the form of pills, tablets, or lozenges, containing any of the substances enumerated in this section and intended for internal use, when the dose recommended does not contain more than one-fourth of an adult medicinal dose of such substance.
For the purpose of this and of every other section of this chapter no box, bottle, or other package shall be regarded as having been labeled "Poison" unless the word "Poison" appears conspicuously thereon, printed in plain, uncondensed gothic letters in red ink.
21 U.S.C. § 209