Anoectochilus formosanus is an important ethnomedicinal plant of Taiwan. We investigated the effect of oral administration of A. formosanus effective fraction (AFEF) on the innate immune response in mice. Male BALB/c mice were treated orally for 2 weeks with 500, 1000 and 1500 mg/kg of AFEF. Primary peritoneal macrophage harvest from mice that administered with AFEF (500 –1500 mg/kg) was directed to activate phagocytosis. AFEF significantly increased interferon-production from lymph node cells by ConA stimulation for 48 hours in AFEF (1500 mg/kg) treated group. AFEF might be the active fraction in activation of innate immunity.