The effect of combining tetanus toxoid in the same syringe with purified Vero cell rabies vaccine (PVRV) was investigated in the 2-1-1 regimen of PVRV. The 2-1-1 regimen alone was as immunogenic as the five-dose regimen, while saving one dose of vaccine and two clinic visits. When aluminium hydroxide-adsorbed tetanus toxoid was used to dissolve PVRV on days 0 (one of the two doses) and 21, the anti-rabies antibody was significantly increased. Aluminium-free tetanus toxoid was ineffective, suggesting that immunoenhancement was due to aluminium adjuvant. In addition, anti-tetanus antibody was unaffected and the side-effects were not increased by such mixing.