Type-specific vaccines containing heat-inactivated herpes simplex hominis virus type 1 or 2 have been developed for the treatment of herpes simplex genitalis. When patients with recurrent herpes genitalis were treated with the type 2 vaccine the clinical course of the disease improved and the eruption-free interval was extended. In severe cases, especially in permanent genital herpes, the concurrent administration of vaccine and immunoglobulin concentrates improved the clinical course of the disease. Antibody titres and the in-vitro stimulation of lymphocytes with phytohaemagglutinin or herpes simplex hominis virus antigens remained constant during administration of the vaccine.