Whether it is normal to have blood clots during menstruation depends on the amount of clots, the color of menstrual blood and the accompanying symptoms, and cannot be generalized. Normal menstrual blood is dark red and non-clotting. If there is more menstrual blood and the blood flow is faster, it will easily clot and there will be shed endometrium mixed with menstrual blood, so a small amount of clots may be normal. If there are too many clots, accompanied by dark red or black blood, lower abdominal pain, irregular menstruation and other symptoms, it is an abnormal phenomenon, which may be caused by cold in the uterus, and can be treated with Chinese herbal medicine or oral medication such as Nuan Gong Qi Wei Wan according to medical advice; if the interval between two periods is short, the periods are long and dripping, there is a possibility of submucosal fibroids, so you should go to the gynecology department for ultrasound, hysteroscopy and other examinations to treat the symptoms. Increased menstrual flow with blood clots may be considered as adenomyosis or adenomyoma, which requires ultrasound examination at the hospital. If the blood flow continues to increase, it may cause secondary anemia in the long run. In addition, during menstruation, you should pay attention to keep warm, especially the lower abdomen, you can use hot water bags or baby warmers to apply hot compresses, and at the same time, you should exercise properly to avoid poor blood flow caused by sedentary, etc.