A case of the girl who underwent multiple hospitalizations is presented. Gastrointestinal disorders were seen in the infancy together with skin rash of allergic type, hypoglycaemia without any clear reason in the fourth year of age, and polyuria with hyponatremia and hypokalemia since the sixth year of age. Mother's lack of concern was unexplainable in view of the deteriorating child's health. Samples of the urine and faeces supplied by the mother have shown the laboratory findings suggesting that potassium chloride was added to the faeces and natrium hydrocarbonate--to the urine. Urine collected during polyuria contained large quantities of furosemide. Long-term follow-up, numerous examinations and performed tests have led to the diagnosis of the particular form of the ill-treated child syndrome, so-called "Munchausenn by proxy" syndrome.