The United Kingdom was the first to take action against hemp in 1928, and by the mid-1930s, cannabis was outlawed in all 48 US states. Hawaii and Alaska had not yet become official states at that time, making access to medical cannabis virtually impossible. In some southwestern states, marijuana was banned due to racial prejudice against Mexicans who used it. As one Texas lawmaker said, all Mexicans are crazy and this (marijuana) is what drives them crazy.
The Harrison Act was a revenue-generating law that provided sanctions for its violation, but did not give states the authority to seize drugs or punish those responsible. In other states, it was prohibited out of fear that heroin addiction would lead to marijuana use, which is the exact opposite of the modern myth of the front door. Marijuana was also banned as part of the Mormon religious prohibitions enacted into law. Until 1939, Harry Anslinger's Federal Bureau of Narcotics (FBN) prosecuted more than 3,000 individual doctors across the country who prescribed drugs with what he considered illegal.
Finally, in 1970, cannabis was officially banned for any use (including medical) with the passage of the Controlled Substances Act (CSA).