AbstractProtective effect of a Japanese traditional herbal medicine, Juzen-taiho-to (TJ-48), which was recently reported to augment host-mediated antifungal actions, inCandidaalbicans-infected mice was further studied. TJ-48, given orally once daily for 5 consecutive days in a dose of 2 g/kg after intravenous infection ofC. albicans, prolonged survival period of infected mice of a C3H/He J strain which is characteristic of functional deficiency of macrophages, but did not that of infected mice of a C3H/He N strain with normal macrophage function. Peritoneal macrophages obtained from C3H/He J mice showed a moderate inhibitory activity againstCandidagrowth in vitro. Theanti-Candidaactivity of the macrophages was augmented by the addition of TJ-48 or some component extracts of TJ-48 to the incubation medium. Among such active component extracts is an extract of Ginseng radix which was demonstrated to enhance the anti-Candida activity of macrophages in vitro and to prolong the survival time of C. albicans-infected C3H/He J mice without effect on C3H/He N mice. On the base of these findings, the mechanisms underlying the protective action of TJ-48 against systemicCandidainfection was discussed in relation with its possible activity to activate the macrophage function.