If one side of the breast is large and the other is small, there is no need for special treatment if it is not obvious and does not affect the appearance. If there is an obvious large and small side, a comprehensive treatment is needed according to the cause. If it is due to congenital developmental abnormalities that cause one side of the breast to be underdeveloped and obviously small, it can only be cured through breast enlargement surgery. If it is due to incorrect breastfeeding habits, often breastfeeding with one side of the breast will lead to more serious atrophy of this side of the breast after weaning, thus resulting in smaller mammary glands, this situation also needs to consider surgical treatment. If the breast size is not uniform on one side due to uneven development of the mammary glands caused by irregular exercise posture and amount of exercise, there is no need to consider surgery for this condition, and it can be improved by adjusting it through exercise.