Women can wash their hair during the physiological period, but only if they take good precautions against cold and warmth. Some people believe that washing hair during physiology will stimulate the nerves in the head and cause headaches, but this phenomenon mostly occurs when washing hair with cold water, and there is no research showing that washing hair with warm water during physiology will cause headaches. Another point of view is that the amount of circulating blood decreases during physiological period of women, washing hair is easy to let the blood in the body concentrated to the head, affecting the blood circulation of the uterus, resulting in a decrease in the amount of menstrual blood or menstrual cramps. However, there is no scientific evidence to prove that washing hair during physiological period will lead to reduced menstrual flow and menstrual cramps. Although you can wash your hair during the physiological period, you should choose to wash your hair in a warm environment with lukewarm water of about 40°C. After washing your hair, you must dry it with a towel or use a hairdryer in a timely manner to avoid catching a cold and do not go to sleep without drying your hair.