The part of the herpes simplex virus type 2 in the development of the cervex carcinoma of women is still an open question. After the serological findings that patients with cervix carcinoma have a higher rate of antibodies against type 2 than healthy women, which were initially published with great expectation, the molecular-virological examinations which were meanwhile carried out by several work groups to find traces of the herpes simplex virus type 2 in the carcinoma cells were negative, except some few but not confirmed cases. Hitherto but the results of transformation of embryonic hamster cells by UV-inactivated virus were the strongest indication for the herpes simplex virus possibly having oncogenic power, although one of the most important demonstrations, i.e. that of the virus DNA, is still lacking even for these transformed cells, which induce fibrosarcoma if injected to newborn hamsters. Possibly the transformation of the normal hamster cell into a tumor cell requires but such a small quantity of the herpes simplex virus DNA that it cannot be traced with the present methods. In connection with the question of the herpes simplex virus being oncogenic also LUPIDON which contains heat-inactivated herpes simplex virus, was examined. For this purpose extended transformation experiments in vitro and animal experiments with new-born hamsters were carried out. All these experiments had a negative result. There is thus no indication for LUPIDON having oncogenic properties.