It is not normal to have blood clots during menstruation. The menstrual flow should be 30-50ml, the blood should be bright red, there should not be blood clots, and the period is within 3-7 days. Usually there is blood clot, which is considered by Chinese medicine to have Qi stagnation and blood stasis. If there is Qi stagnation and blood stasis, there will be a large amount of blood clots in the menstrual blood, and serious pain in the lower abdomen will occur. Menstrual blood with blood clots, like having endometrial polyps or lesions of the endometrium, may also appear to have a large amount of blood clots during menstruation, at which time you can go to the hospital for ultrasound to make a clear diagnosis. If it suggests thickening of the endothelium and uneven echogenicity of the endothelium, there will be blood clots during menstruation. Submucosal fibroids, too, can present with heavy blood clots during menstruation. A short cycle with a period of more than 20 days, a long period with a trailing condition, and the presence of a large number of blood clots is a possibility of submucosal myoma. At this time, you must go to the hospital for the appropriate examination and then choose the appropriate medication for symptomatic treatment according to the examination results.