Sudden hair loss in women is divided into two kinds: pathological and physiological. Physiological and season, mental tension, sleep do not need special treatment, the symptoms of hair loss can gradually disappear after the change of living habits. Pathological hair loss includes: 1. Pernicious anemia due to poor absorption of vitamin B12, which reduces the number of red blood cells in the body and cannot supply the substances needed for hair growth and leads to massive hair loss. 2. Patients suffering from hyperthyroidism cause severe hair loss due to endocrine metabolic disorders, take drugs for hyperthyroidism such as propylthiouracil, and the symptoms of hair loss can disappear after the level of thyroid hormone returns to normal. 3, The symptoms of hair loss can be gradually improved after stopping the medication. 4. The symptoms of hair loss can be disappeared after a period of time when the hormone level in the body returns to normal due to a sudden drop in the level of hormones in the body.