Neutralising antibody responses to six post-exposure regimens of human diploid cell strain rabies vaccine with or without human rabies immune globulin (HRIG) were studied in 98 patients. The total amount of vaccine used was 22-34% of that required by conventional regimens. Vaccine was given at multiple sites intradermally or subcutaneously with or without adjuvant. Antibody was detectable within 7 days of the first dose in all subjects only in the groups given 0.1 ml intradermally at 8 sites. From day 14 onwards all groups showed an excellent antibody response; there was little difference between the various regimens. Suppression of the response to 8-site intradermal vaccination by a large dose of HRIG could be prevented by giving the second dose of vaccine on day 7 rather than day 14.