Recurrent herpes simplex infections present distinct therapeutic problems which have led to various approaches to treatment. At a recent national dermatologic meeting, it was suggested that favorable results followed vaccination using unmodified material taken directly from the primary active disease site. We have no experience with this approach which may be of value, but it is attendant with some danger as exemplified by the following cases. Case1.—R. W., a 22-year-old white man, was first seen in 1952 after complaints about a penile and abdominal eruption. Physical Examination.—The man was well except for a vesicular and crusted eruption superimposed on an erythematous and edematous base. Two small areas on the penile shaft and the left upper abdominal wall were involved. History, clinical features, and laboratory studies confirmed the herpes simplex virus as the etiologic agent in both sites. History.—The first attack occurred on the penile