Between 1919 and 1933, the United States imposed a nationwide ban on the production, sale, and transportation of alcoholic beverages, known as Prohibition. While this era is often remembered for its connection to organized crime figures like Al Capone and the rise of secret bars called speakeasies, it also involved a more sinister government strategy: the deliberate poisoning of industrial alcohol to prevent its use as a drink. The Treasury Department made industrial alcohol more dangerous by adding substances like methanol, a toxic chemical that is nearly impossible to detect by taste or smell. This process, known as denaturation, rendered the alcohol unsuitable for human consumption, but it also made it deadly if ingested. Methanol is chemically similar to ethanol, the type of alcohol found in drinks, but it is far more dangerous. In the human body, methanol is converted into toxic compounds that can damage the optic nerve and the central nervous system. Even small amounts can cause blindness, and larger doses can be fatal. Despite knowing the risks, authorities believed the dangers were an acceptable trade-off to prevent the misuse of industrial alcohol. This policy, however, led to widespread health crises, as people who sought out illicit alcohol often unknowingly consumed these toxic substances. Doctors and coroners across the country raised alarms about the rising number of poisoning cases, but their concerns were largely ignored by the government. Estimates suggest that as many as 10,000 people may have died from drinking denatured alcohol during Prohibition, with many more suffering from blindness or neurological damage. In cities like New York, hospitals saw a surge in patients with similar symptoms, including severe vision loss, abdominal pain, and mental confusion. Coroners identified methanol poisoning as a common cause of death, but their warnings did not lead to a change in policy. The government’s approach highlighted the unintended consequences of a prohibitionist strategy that failed to consider public health risks. While Prohibition aimed to reduce alcohol-related moral and social issues, the methods used to enforce it resulted in a surge of health dangers, particularly for the working class, who had limited access to safer alternatives. This dark chapter of American history raises a broader question: how far can a government go in the name of public health before its actions become a form of harm to its own citizens?