The discharge of a lump of black sticky material during menstruation may be a normal phenomenon, or it may be caused by endometritis, pelvic inflammatory disease, as well as other diseases such as vaginitis. 1. Normal phenomenon: If the menstrual blood stays in the uterine cavity for a long time or the amount of menstrual flow is relatively small, a lump of black sticky menstrual blood may be discharged. This is a normal physiological phenomenon and does not require treatment. 2. Endometritis: Endometritis is caused by pathogens such as Neisseria gonorrhea, Mycoplasma, and anaerobic bacteria. Patients will have lower abdominal pain, increased menstrual flow, prolonged menstrual period and other symptoms, some patients endometrium and cervical exudate and menstrual blood mixed, there will be menstrual discharge of a pile of black thick material symptoms. 3. Pelvic inflammatory disease: Pelvic inflammatory disease is caused by pathogens such as Staphylococcus aureus, hemolytic streptococcus, Chlamydia trachomatis, Neisseria gonorrhoeae and other pathogens. Patients will show prolonged menstruation, increased menstrual flow, and some patients’ menstrual blood stays in the uterus for a long period of time, which will be manifested as menstrual discharge of a heap of black sticky material. 4. Other: patients with menstrual discharge of a pile of black sticky material is also considered to be vaginitis, cervicitis and other diseases. If physiological factors are ruled out, it is more likely to be caused by disease, and the patient needs to consult a doctor in time to check the cause of the disease, and the doctor will choose the appropriate measures for the cause of the disease to be treated.