Eating disorders in early childhood are the same frequency in boys and girls. During adolescence eating disorders are ten (10) times more frequent in girls than in boys. Worrying is the fact that eating disorders are the third chronic illness among adolescents after obesity and asthma. Depicting this adolescent we tried to show difficulty of treatment of this disorder, where in the beginning is important to stabilize body weight and prevent somatic damages such as: heart damage, amenorrhoea, changes in EKG (electrocardiogram) and electrolyte dysbalance that could endanger the life of patient. Simultaneously it is important to recognize and treat comorbid psychological disturbances such as in this case: depression, delusions with occasional psychotic reactions combined with unrealistic thinking about the layout of her own body. There is still no cure for the treatment of eating disorders which are in growing number of reports among male adolescents.