The nutrients of breast milk can fully meet the needs of growth and development of infants within six months, and it is the best food for infants. If the exclusively breastfed child is thin, to analyze and deal with the following aspects: assessed by the doctor to determine the child’s nutritional status, some mothers like to use their own children compared to other children, that their own child is thin. The doctor needs to check the height and weight after judgment, only below the same age, the same sex, the same height of the child’s standard weight of more than two standard deviations, can be diagnosed as wasting. If the diagnosis of wasting, to find the causes of wasting, the specific reasons are as follows: 1, insufficient nutritional intake, may be insufficient amount of breast milk, did not add other foods in time, after six months did not give the child timely addition of complementary foods or add complementary foods are not the right species; 2, their own physical quality is too poor, the combination of diseases, such as congenital cleft lip and palate, allergic enteritis, chronic diarrhea, malabsorption and other diseases, resulting in eating into the digestive absorption can not be; 3, fast growth or diseases, the child’s growth is too fast, or the disease is not digested. 3, fast growth or suffering from disease, the increase in nutritional demand, resulting in relative nutritional deficiencies. For example, measles, tuberculosis recovery period, growth and development is particularly fast, such as premature birth, twin births need to catch up with the growth, this time the relative lack of nutrition. Only for different reasons, take different treatment methods can solve the problem.