The persistence of latent human immunodeficiency virus type 1 (HIV-1)-infected cellular reservoirs, despite prolonged treatment with highly active antiretroviral therapy (HAART), represents a major hurdle to virus eradication. In this study, we evaluated the effect of Japanese herbal medicine on the induction of HIV-1 replication in latently infected monocytic cell line, U1, in order to eradicate virus efficiently. We found that Mao-to was able to induce HIV-1 replication either alone or in combination with tumor necrosis factor-alpha (TNF-alpha). Among the four components of Mao-to, only Ephedrae herba had strong effects in inducing HIV-1 replication. Analysis by Western blotting revealed that Ephedrae herba induced the nuclear translocation of nuclear factor-kappa B (NF-kappaB). Reporter assay data also showed that Ephedrae herba and, slightly, Mao-to activated the NF-kappaB promoter, indicating that these herbal agents may induce HIV-1 replication through NF-kappaB activation. These findings suggest that Mao-to and its component, Ephedrea herba, may be good candidates to augment HAART by inducing the expression of latent HIV-1 with the ultimate goal of eliminating persistent viral reservoirs in individuals infected with HIV-1.