If one breast is enlarged during puberty, it may be due to growth and development. As long as the size of both breasts is not particularly obvious and not accompanied by pain, there is no need to treat it intentionally. For breastfeeding women, if the enlargement of one breast is related to milk secretion and the baby’s breastfeeding habits, and is not accompanied by uncomfortable symptoms, there is no need to treat it, and it needs to be adjusted through normal breastfeeding habits. You should wear loose underwear and keep your breast area fresh and clean, and breastfeed evenly on both sides. If your breasts are enlarged with pain or lumps, you should go to the hospital for an ultrasound examination to consider breast hyperplasia, mastitis, tumors, etc., which need to be diagnosed and treated accordingly. Breast diseases should not be angry, to prevent endocrine disorders aggravate the condition.