If one side of the breast is enlarged during puberty, it may be caused by growth and development. As long as the size of both breasts is not particularly obvious and is not accompanied by painful sensations, there is no need for deliberate treatment. For women who are breastfeeding, 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 for treatment. You should wear loose underwear and keep the breast area fresh and clean, and breastfeed both breasts evenly when breastfeeding. If your breasts are enlarged with pain or lumps, you should go to the hospital for an ultrasound examination in time to consider breast enlargement, mastitis, tumors, etc., which should be diagnosed and treated accordingly. The most important thing to avoid in breast diseases is anger, to prevent endocrine disorders aggravate the disease.