The invention discloses a medicament for treating breast cancer, which comprises the following raw materials: costus root, rhizoma cyperi, radix curcumae, dried orange peel, cortex magnoliae officinalis, dangshen, fried bighead atractylodes rhizome, glossy privet fruit, angelica, milk vetch, Chinese wolfberry, radix scutellariae, coptis, tuber pinellia, morel, solanum lyratum, bupleurum, agrimony, radix rehmanniae, barbed skullcap herb, dandelion, oyster, prepared turtle shell, forsythia, euphorbia helioscopia, citron, corydalis tuber, rhizoma bolbostemmae, American ginseng, white peony root, licorice, glabrous greenbrier rhizome, chuanxiong rhizome, mint, buttercup root, tulip bulb, sarcandra glabra, prunella vulgaris, gizzard pepsin, common burreed rhizome, rhizoma zedoariae, red sage root, fried mastic and fried myrrh. The medicament disclosed by the invention has an obvious effect on treating breast cancer, can be used for treating both principal and secondary aspects of the disease, has the functions of inhibiting the growth and migration of cancer cells, improving the gastrointestinal functions of patients and improving the immunity, and does not have toxic side reactions. The effective rate reaches 92.6%, and the effect taking rate reaches 75%. The medicament disclosed by the invention has the characteristics of exact effect and low price, can be used for quickly curing the breast cancer, and can be easily accepted by patients.