If there is only a little menstrual flow, it means that there may be qi and blood weakness or blood stasis, and there may be the following situations: 1) If the patient’s menstrual flow is small, pale in color, or delayed after the onset of menstruation, it is considered to be due to the low menstrual flow caused by blood deficiency, which can be seen in women suffering from various chronic diseases or women who have long been overdieting and are too thin in size. 2) If there is a delay in the onset of menstruation, the menstrual flow is small, and the color of menstruation is dark, it is considered to be due to kidney deficiency. If the menstrual period is delayed, the amount of menstruation is small and the color is dark, the low menstrual flow is mostly considered to be caused by kidney deficiency, which is mostly caused by overwork, poor rest and lack of moderation in daily life. 3. If the amount of menstrual flow is small and accompanied by obvious clots of blood, the color is black, dark and accompanied by abdominal pain and the fear of cold, it is considered to be caused by the invasion of cold gas into the uterus.