the present invention relates to use of a composition in the manufacture of a health care product or medicament for preventing and treating leucopenia induced by radiotherapy or chemotherapy . the composition is made from raw materials comprising 5 to 200 parts by weight of ganoderma , 5 to 150 parts by weight of radix panacis quinquefolii or radix et rhizoma ginseng , 1 to 90 parts by weight of fermented cordyceps sinensis powder and / or 1 to 120 parts by weight of cordyceps , or is a composition consisting of water and / or alcohol extracts of the above raw materials as active components .