Following the publication of Maxfield's results in the treatment of radiation sickness by pyridoxine hydrochloride (vitamin B6) in 1943 (6), we became interested in this drug and subsequently began its use in radiation sickness at The Henry Ford Hospital. In order to give the drug a thorough trial, it was decided to limit its use to the more severe cases and not to use it prophylactically. With this in view, we arbitrarily classified our cases of radiation sickness into four groups: (1) mild (anorexia and some nausea); (2) moderate (rather severe nausea, distaste for food, and occasional vomiting); (3) severe (pronounced nausea and frequent vomiting); (4) late or inflammatory symptoms due to proctitis, enteritis, and cystitis. No medication was offered to patients falling in the first group. Those in the other three groups received intravenous injections of 25 to 50 mg. of pyridoxine hydrochloride, in the form of Hexabetalin, beginning with the onset of symptoms. No other medication was given to any patie...