Prohibition was a rather tumultuous time in the country's history, lasting from 1920-1933. which substance was famously outlawed?

The answer is alcohol. The US had a nationwide ban during these years of the presence of alcohol beverages that caused family violence and corruption. It was led by Pietistic Protestants that wanted to end the problem. However, there were criminals that still continued to supply alcohol to different cities. The Prohibition was not able to totally stop alcohol and be consumed by the people. But it did stop half of the consumption.