Capone was first diagnosed with syphilis while serving his 11-year sentence for tax fraud. Following his transfer to Alcatraz Federal Penitentiary in 1934, he began to show signs of confusion and disorientation. He was officially diagnosed with neurosyphilis in 1938. In 1942, he was one of the first Americans to receive the antibiotic penicillin as treatment for syphilis after the drug began to be mass-produced.

Source: Men's Health