The preparation and characterization of an immunostimulating complex (ISCOM) preparation containing several HSV-1 glycoproteins, including the major glycoproteins B and D is described. The multi-glycoprotein HSV-1 ISCOM preparation was obtained from a gradient-purified aqueous HSV-1 antigen preparation following extraction from infected cells using a zwitterionic detergent. With polyclonal and monoclonal antibodies to HSV-1 glycoproteins in enzyme-linked immunosorbent assay, SDS-polyacrylamide gel electrophoresis and radioimmunoprecipitation techniques, the HSV-1 ISCOM preparation was shown to contain glycoproteins B, C, D, E, H and I, although further, additional proteins were also present. The DNA content of HSV-1 ISCOMs was determined using a 3H-thymidine labelling method. The protein and DNA contents of the HSV-1 ISCOM preparation are discussed with reference to the potentialities of the preparation as a vaccine for use in human beings.