Menstruation refers to the onset of menstruation. The blood clots in menstruation like a big pile of rotten meat are considered to be related to ordinary heavy menstruation, uterine fibroids, adenomyosis, malignant lesions and so on. 1. Plain heavy menstruation: If women have heavy menstruation since the onset of menstruation, due to the position and other factors will lead to menstrual blood retention in the vagina, while the menstrual blood reacts with the air and coagulates, so there will be a large blood clot discharged after the activity, there is no need to be too nervous at this time, and if necessary, you need to take iron and other blood replenishment therapy after the menstrual period is cleansed. 2. Uterine fibroids and adenomyoma: as these two diseases will cause the increase of uterine volume and endometrial surface area, and menstruation is formed due to the stripping of endometrium, so women will have heavy menstrual flow with blood clots and prolonged menstruation period, and so on. 3. Malignant lesions: if women have malignant lesions such as endometrial cancer and cervical cancer, due to the rapid growth of cancer cells, the invasion of local blood vessels will lead to heavy menstrual flow with blood clots. For women who have blood clots like a pile of rotten meat during menstruation, it is recommended that they go to gynecology department of regular hospitals to improve ultrasound and other relevant examinations, and then take active treatment under the guidance of doctors after the cause of the disease is clarified.