Minnesota Statutes Health (Ch. 144-159) § 151.23. Poisons must be labeled

It shall be unlawful for any person to sell at retail any poison without affixing to the package or receptacle containing the same a label conspicuously bearing the word “poison,” and the name and the business address of the seller, and being satisfied that such poison is to be legitimately used. This section shall not apply to the sale of poison on a physician's written prescription or in the original package of the manufacturer.