If you dye your hair during menstruation, you may experience allergic symptoms, or there may be no obvious discomfort, there are individual differences. During menstruation, a woman’s body resistance is relatively low, and if she has a sensitive body, the chemicals in the hair dye may be absorbed through the scalp, resulting in allergic reactions such as redness, swelling, itching, and rashes, which are hazardous to her health. However, if the woman does not belong to the sensitive body, after the menstrual hair coloring may not necessarily appear obvious symptoms of discomfort, there may not be any reaction, but the hair dye will be more or less damaging to the body, it is best to avoid frequent hair coloring. Menstruation is a special period, we should pay attention to menstrual hygiene and care, after hair coloring, pay attention to observe whether there is discomfort, if there is an allergic reaction to wash in a timely manner, seek medical treatment.