AHCC is a nutritional food that has been broadly adopted in Japan as well as other countries. Several laboratories have demonstrated that AHCC has immune modulating effect. Increasing immunity against bird flu virus, H5N1, may help to prevent the next pandemic. We hypothesize that uptaking AHCC improve immunity against infection with this virus. Administration of AHCC for 7 days effectively improved survival rate by 30%, and this effect can last for 3 to 4 weeks. Our results indicate a potential role of AHCC in helping to build up immunity for preventing the pandemic of bird flu.