The causes of black and brown menstrual blood and its adjustment methods are as follows: 1. The patient can take Yuanhu Pain Relief Tablets to regulate. 3. Real cold, due to cold stimulation before or after menstruation, resulting in cold invasion of the uterus, the patient will show postponed menstruation, dark brown menstruation, low volume with abdominal pain. Patients can take dysmenorrhea pills to regulate the symptoms.