The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
Because it is a herb specifically indicated to treat uterine cysts as can be seen on Flying Squirrel Faeces's page.
Its main actions are: Disperses congealed Blood in the lower abdomen and uterus and relieves pain. Promotes childhood nutrition with Cold Stagnation and focal abdominal swelling.