Radithor was a patent medicine that consisted of triple-distilled water containing at least 1 microcurie each of radium-226 and 228. Though it was suspected at the time, Radithor has since been proven unequivocally to be a quack cure that ended up doing more harm than good.

Radithor was manufactured from 1918 to 1928 by Bailey Radium Laboratories, Inc. in East Orange, New Jersey. The owner of the company and the developer of the product, Dr. William J. A. Bailey, was a college dropout and, alarmingly, not a medical doctor. Bailey touted the product as "A Cure for the Living Dead" meaning a cure for mental illness and retardation.

The most famous death by Radithor was that of American socialite and steel tycoon Eben McBurney Byers. After injuring his arm in a fall, Byers was prescribed Radithor by his physician. Byers drank nearly 1,400 bottles over three years, stopping the remedy in 1930. By this time, it was too late. He had accumulated such a vast amount of radium in his bones that most of his jaw had to be surgically removed, his brain was severely abscessed, and holes formed in his skull. Byers died of severe radium poisoning in 1931 and his corpse had to be interred in a lead coffin.

The death of Eben Byers was the wake-up call the medical community needed to realize the hazardous nature of this so-called "miracle cure" and marked the beginning of the end for the radium water remedy phenomenon.

Sources:
http://www.orau.org/ptp/collection/quackcures/radith.htm
http://www.museumofquackery.com/devices/radium.htm
http://listverse.com/2010/03/25/10-famous-incidences-of-death-by-radiation/