INTRODUCTION: Enterocutaneous fistula is defined as an abnormal connection between the gastrointestinal tract and the skin. In addition to the early recognition and treatment of sepsis, nutritional support, wound management, the adequate replacement of lost fluids with a properly set and timely rehydration treatment, together with the control of fistula production represent the first steps in treatment management. MATERIAL AND METHODS: The authors present an overview of oral rehydration therapy, describing the properties and effects of individual solutions on fistula. The absorption of fluids and electrolytes into the gastrointestinal tract is performed by the group of sodium-dependent glucose cotransporters (sodium-glucose linked transporter, SGLT1). DISCUSSION: The water and electrolyte absorption mechanisms described in the article can be used in the treatment of a patient with a high fistula. The amount of administered hypotonic fluids (water, tea) should not exceed 500 ml/day. The remaining volume, depending on fistula loss, must be supplemented with isoosmolar fluids. With a good tolerance of oral rehydration solutions and compliance with the other steps of treatment, it is possible to remain on oral intake during the entire duration of treatment without the need to prohibit it completely, thus improving the patient's overall comfort. CONCLUSION: Reducing the intake of hypotonic fluids (tap water, tea) and administering an isotonic solution help to reduce the production of the fistula, thereby contributing to its spontaneous closure.