Zingiber officinale and Hizikia fusiforme(sea weed fusiforme) have long been used for food sources in Korea. The present study was performed to investigate the ex vivo effect of Zingiber officinale and Hizikia fusiforme on NO production in macrophage of mice. Seven to eight week old mices(Balb/c) were fed chew diet ad libitum and water extract of Zingiber officinale and Hizikia fusiforme was administrated orally at two different concentrations (50 and 500 mg/kg B.W.). every other day for two or four weeks NO(nitric oxide) production by activated macrophage was assessed by measuring nitrite, the stable NO metabolite, using Griess reaction assay. NO production were significantly enhanced in Zingiber officinale group at 500 mg/kg B.W. and in Hizikia fusiforme group at 50 mg/kg B.W. compared to the coresponding control groups. In conclusion, this study may suggest that Zingiber officinale and Hizikia fusiforme(sea weed fusiforme) extracts enhance the immune function by regulating NO production in macrophages of mice.