The eleven-year-old girl’s breasts grow on one side and not on the other, considering that it may be related to malnutrition, wear unreasonable, cystic hyperplasia of the breast and many other factors, generally can be improved by adjusting the diet, maintain a healthy sleep posture and other methods. 1. Malnutrition: Not being able to get enough protein, fat and other nutrients from the daily diet may also affect the development of a girl’s breasts. In this period must pay attention to ensure sufficient nutrient intake, three meals should pay attention to meat and vegetarian reasonable combination. 2. wear unreasonable: girls wear unreasonable bra will also cause pressure on the local breast tissue, affecting the development of breasts, parents usually must pay attention to not let the girl through the tight bra. 3. Breast cystic hyperplasia: Breast cystic hyperplasia can also lead to 11-year-old girls on one side of the breast enlargement, palpation can be touched cystic swelling, can improve chest ultrasound, chest CT and other clear diagnosis. There are other clinical reasons why an 11-year-old girl’s breasts grow on one side and not on the other, so it is recommended that you take the girl to the hospital to get a clear picture of the cause of the problem and to receive treatment for the cause of the problem.