A method for reducing liver and kidney damage caused by radiotherapy is disclosed. The method comprises administering a herbal medicinal composition to a subject in need, wherein the herbal medicinal composition comprises 1.3-5.3 parts by weight of Chaihu, 2.2-8.8 parts by weight of Hunagqing, 1.8-7.0 parts by weight of Panxia, 1.8-7.0 parts by weight of Chishaoyao, 0.5-1.8 parts by weight of Dahuang, 1.3-5.3 parts by weight of Zhishi, 2.2-8.8 parts by weight of Hungtsao, 4.4-17.5 parts by weight of Fuling, 1.8-7.0 parts by weight of Chuling, 2.2-8.8 parts by weight of Zerxie, 1.8-7.0 parts by weight of Changchu, 1.3-5.3 parts by weight of Mahuang, 1.8-7.0 parts by weight of Dansheng, 2.2-8.8 parts by weight of Chuanxiong, 2.2-8.8 parts by weight of Wuchuyu, 2.2-8.8 parts by weight of Tienma, 1.3-5.3 parts by weight of Ginseng, and 1.3-5.3 parts by weight of Chuanchi.