It may be normal or endocrine disorder on the second day of a woman’s menstruation, as follows: a. Normal phenomenon: It may be that on the first day of menstruation, the endometrium has mostly shed, so the amount is more on the first day, but on the second day the endometrium peels off very little, and the menstrual volume will be very little. As long as the total menstrual volume of women exceeds 20mL during the whole menstrual period, it is a normal physiological performance and can generally be treated without special treatment. Second, endocrine disorder: If a woman has a small amount on the first day and an even smaller amount on the second day, while the total amount during the whole menstrual period is less than 20mL or more, it should be considered that it may be due to endocrine disorder causing the phenomenon of menstrual hypomenorrhea.