To the Editor.— In QUESTIONS AND ANSWERS Albert Sabin, MD, states in his answer (238:63, 1977) regarding the use of ether (diethyl) in the treatment of herpes simplex: see no reason why a physician cannot supply a screwcapped or cork-stoppered vial containing 30 to 60 ml of ether directly to the patient. I wish to point out that diethyl ether, once opened from its sealed container and exposed to air, oxidizes to form peroxides that are highly explosive. This supply of ether, if stored, would constitute an extreme hazard not only to the patient and his family but also to the physician and his office personnel storing a larger, open bottle of ether to supply patients.