Keeley graduated at the Rush Medical College, Chicago, in 1863, and later entered the Union Army as a surgeon. At the end of the war he moved to Dwight, Illinois, where he began his private medical practice. There, in 1880, he opened a sanatorium for persons addicted to the immoderate use of alcohol and opium. He asserted that "Alcoholism is a disease and I can cure it." His treatment centered on a secret preparation that he said contained bichloride of gold. However, chemical analysis revealed that the proprietary tonic contained 27.55% alcohol plus ammonium chloride, aloin and tincture of cinchona but no gold. His hypodermic injections contained sulfate of strychnine, atropine and boracic acid.