Dyeing hair when menstruation is not good, mainly because of the following points: First, in the menstruation if the dyeing of hair, sitting time will be relatively long, may lead to can not change the sanitary napkin in time, and vulvar local inflammation and other reactions. Second, although menstruation is a normal physiological phenomenon of women, but due to the decline in body resistance during menstruation, hair coloring will have an adverse effect on the body, mainly hair dye will contain toxic and harmful chemicals, so it will bring adverse effects on physical health. When the body’s resistance drops, do not apply hair dye with a certain degree of toxicity, it is recommended that after the menstrual period is clean, then consider dyeing hair, but it is best to reduce the number of times of dyeing hair, the damage to the health of the body will also be reduced.