In the 1901 U.S. Supreme Court case, Capital City Dairy Company v. Ohio, the court upheld a state law that regulated the sale of milk and cream within its borders. The dairy company challenged an Ohio statute requiring all vendors to label containers with their product's grade according to standards set by state officials. They argued this was unconstitutional as it violated both due process and equal protection clauses of the Fourteenth Amendment because it interfered with interstate commerce and imposed unreasonable restrictions on businesses in other states selling products in Ohio. However, Justice John Marshall Harlan delivered a unanimous decision upholding the law stating that while states cannot directly regulate interstate commerce or discriminate against out-of-state businesses, they can enact laws protecting public health even if those laws indirectly affect such commerce or businesses from other states. The ruling affirmed that individual states have broad powers under their police authority to protect public health and safety which includes regulating food quality standards within their jurisdiction despite any incidental impact on interstate trade.

The dissenting opinion in the Capital City Dairy Company v. Ohio case argued that the law, which required all milk sold within certain cities to be bottled at the source of production, was not a reasonable exercise of police power by the state. The justice believed it infringed upon interstate commerce and violated equal protection under the Fourteenth Amendment. They contended that there was no substantial health risk associated with transporting milk in large containers for bottling elsewhere, as long as sanitary conditions were maintained throughout this process. Therefore, they saw no valid public interest being served by this restriction on trade and competition among dairy companies from different states.