Breasts suddenly become bigger may be caused by physiological factors, may be taking drugs and other factors, may also be caused by the disease of breast hyperplasia factors, more common types are as follows: 1. Physiological factors: the patient is fat, fat accumulation on both sides of the breast, causing breast enlargement. In addition, rising hormone levels will promote mammary gland development caused by breast enlargement, puberty development, pregnancy, breastfeeding and so on, will cause hormone levels to rise, causing breast enlargement. 2. Taking drugs: Taking estrogenic drugs such as estradiol can also cause hormone levels to rise, resulting in larger breasts. 3. Pathological factors: There are more pathogenic factors that cause breast enlargement, such as breast hyperplasia and breast tumor. (1) Breast hyperplasia: it can cause the disproportion of estrogen in the patient, which will lead to the overgrowth of the breast finger, as well as the increase of prolactin in the patient, which will lead to the growth of the breast and cause the breast to become bigger. (2) Breast cancer: breast lumps appear, causing one or both breasts to become larger. If you find that your breasts suddenly become bigger and accompanied by pain and swelling and other symptoms, you need to go to the hospital as soon as possible to find out the cause of the disease and follow the doctor’s instructions for treatment, and the drugs should be used under the guidance of the doctor, do not take the drugs on your own.