The United States v. Carolene Products Co. case involved the Filled Milk Act, which banned the shipment of skimmed milk mixed with any fat or oil other than milk fat. Carolene Products Co. was indicted for violating the Act by shipping "Milnut," a mixture of condensed skimmed milk and coconut oil. They argued that the Act went beyond Congress's power and violated the Tenth and Fifth Amendments by denying equal protection of the laws and due process of law. The court, however, upheld the Act as a valid exercise of Congress's power to regulate interstate commerce and prevent the shipment of harmful products. The Filled Milk Act was passed after extensive investigations that concluded using filled milk as a substitute for pure milk was harmful to public health and facilitated fraud. The prohibition of the appellee's product was a reasonable means of protecting public health. The court upheld the constitutionality of the statute and ruled that the prohibition of filled milk in interstate commerce was subject only to the restrictions of the Fifth Amendment.

The Filled Milk Act can address a specific issue even if it fails to address another, and derogatory terms used in the statute do not prevent judicial review of its constitutionality. The statute's characterization of filled milk as harmful is a declaration of legislative findings to support its constitutionality. The validity of the statute can be challenged by showing that the facts on which it is based no longer exist or that it is not supported by reason when applied to a particular article. However, the decision is ultimately for Congress, and neither a court nor a jury can substitute their verdict for it. The court found that the prohibition of shipping the appellee's product in interstate commerce is constitutional and falls under the power to regulate interstate commerce. The allegation that the product is injurious to public health is an issue of fact to be determined at trial.