Herbert Lee Stivers told the Los Angeles Times that a German girl called Mona had fooled him into smuggling a vial of liquid to Goering's cell hidden in a fountain pen, telling him it was medicine.
Mr Stivers, now 78, said he had been persuaded to tell his story after nearly 60 years of silence by his daughter, and by the fact that the statute of limitations on his crime had expired. His telephone had been disconnected yesterday.
Historians reacted cautiously to Mr Stiver's confession.
Most said it was plausible, but warned that it might now be impossible to determine the truth of what had happened.