There are various reasons for brown blood in the vagina in the absence of menstruation, and relevant laboratory tests are needed to determine the cause of the abnormal bleeding. In the case of brown blood in the vagina without a period, it is important to first determine if the patient is pregnant. It is recommended that a serum human chorionic gonadotropin test be performed at a local hospital. If the result is positive, then the patient is pregnant, and if the result is negative, then the patient is not pregnant. If the patient is pregnant, then the brown blood is considered to be the result of a preterm miscarriage in early pregnancy. Some pregnant women experience preterm miscarriage in early pregnancy due to embryonic dysplasia. Usually, treatment is needed to preserve the pregnancy. The vaginal bleeding may disappear on its own after successful fertility treatment. If the patient is not pregnant, a gynecologic examination and gynecologic ultrasound are needed to determine the cause of the bleeding. Usually, fibroids, endometrial polyps, cervical lesions, etc. need to be ruled out. These diseases are common causes of abnormal vaginal bleeding. If necessary, inpatient surgery is required to resolve the abnormal vaginal bleeding. In conclusion, abnormal vaginal bleeding without menstruation needs to be treated at a local hospital to identify the cause.