Ovarian effusion may be a fluid dark area in the ovary. In fact, the effusion is an enlarged follicle. Generally, if the follicle exceeds 3.0cm, it is an ovarian cyst. It may be a physiological ovarian cyst. Because the enlarged follicle may not be discharged normally, it may be tending to become a luteinized cyst. It seems that there is a dark area on the B ultrasound, which is a physiological luteal sac. In general, B-ultrasound can be rechecked within 3-7 days after menstruation is clean, and in most cases, it can subside by itself. If there is no spontaneous regression, the diameter of the ovarian cyst is less than 5cm, which is generally a functional cyst. You can consider taking Guizhi Fuling capsule and other drugs to promote blood circulation and remove blood stasis for a period of time, and recheck once every 2-3 months. If the diameter of the cyst is greater than 5cm, it may be an ovarian tumor. Ovarian cysts larger than 5cm have surgical indications and generally need to be treated by surgery. If accompanied by progressive increased dysmenorrhea and sexual intercourse pain, pelvic pain nodules, etc., it may be endometriosis cysts. Therefore, if there is fluid in the ovary, it may be an ovarian cyst. It needs to be comprehensively analyzed according to the specific size of the cyst, as well as clinical related history and signs, to make a clear diagnosis, and then consider targeted symptomatic treatment.