You can't drink siwutang during menstruation. Generally, don't take drugs that promote blood circulation and replenish blood when menstruating. Siwutang is a medicine for enriching blood. Eating it during menstruation may lead to less menstrual flow. This can be eaten after the menstrual period is clean. Generally, it can be eaten for 1-2 weeks, which has a good blood-enriching effect. Long-term menstruation will be normal and the face will turn white and red.