Some doctors knew it would be a failure from the beginning and worked actively to repeal it, believing (correctly) that by limiting access to relatively safer, drinkable alcohol, more people--and especially poorer people--would drink lethal industrial alcohol.

Charles Norris, who created the Office of Chief Medical Examiner of New York City, was an impassioned critic of Prohibition and wrote many editorials about the dangers of the law, especially as the government, in an effort to make industrial alcohol less palatable, required manufacturers to add in more and more toxins.

For more on his work and his thoughts on Prohibition, I enjoyed THE POISONER'S HANDBOOK by Deborah Blum

Another popular recent book on this one is Last Call by Daniel Okrent. Fascinating layman's history of the movement from beginning to end.