Breast cancer chemotherapy hair loss is related to the individual’s physical condition as well as the chemotherapy regimen, and the exact timing is variable, starting in the second week of chemotherapy for some patients. Hair loss is one of the most common side effects of chemotherapy because while chemotherapy kills the cancer cells, any rapidly dividing cells similar to the cancer cells are harmed by the chemotherapy drugs, which is the case for the scalp cells, thus causing 90% of the hair to fall out. At the beginning of chemotherapy, the hair does not fall out very much, and as the chemotherapy progresses, the hair slowly thins and then falls out. Hair loss is only temporary, after the chemotherapy is over, the damaged hair follicles will gradually return to normal, and new hair will start to grow gradually in 1~2 months, and after half a year or a year, the hair will return to its previous appearance. It is recommended to follow the doctor’s advice to cooperate with the treatment, when hair loss occurs, you can wear a wig, do not feel excessive mental stress.