The invention relates to a drug for treating endometrioma, which is prepared from the following raw herbal materials in terms of weight proportions: 10 parts of rhizoma cyperi, 8 parts of radix aucklandiae, 8 parts of rhizoma corydalis, 12 parts of curcuma zedoary, 9 parts of wild chervil, 8 parts of sappan wood and 6 parts of cinnamomum cassia. The inventor thinks that the basic pathogenesis of endometrioma is that blood is stagnated in uterus, so that endometrioma is properly treated by means of dispersing liver, activating blood circulation, dispersing blood stasis and eliminating mass. The drug utilizes the following features: the rhizoma cyperi is used for discharging liver, relieving depression, regulating menstruation and relieving pain; the radix aucklandiae is used for tonifying spleen and promoting qi circulation; the rhizoma corydalis is used for activating blood circulation, promoting qi circulation and relieving pain; the curcuma zedoary is used for breaking stagnated blood and removing stagnation; the wild chervil is used for removing blood stasis and promoting tissue regeneration; the sappan wood is used for activating blood circulation and removing blood stasis; the cinnamomum cassia is used for eliminating cold, relieving pain, warming channels and dredging collaterals. All the raw herbal materials are used together for achieving the effects of dispersing liver, activating blood circulation, dispersing blood stasis and eliminating mass, so that endometrioma is effectively treated. Proved by clinical experiments, the drug for treating endometrioma can be safely and effectively used for treating endometrioma.