Patients who are dehydrated need to be supplemented with the appropriate electrolytes depending on the type of dehydration most effectively. Clinically dehydration is categorized as hypertonic, isotonic and hypotonic. Patients with hypertonic dehydration should be supplemented with a hypotonic solution, which can be applied to 0.45% sodium chloride solution at rest. Isotonic dehydration can be supplemented with saline i.e. 0.9% sodium chloride solution is sufficient. In case of hypotonic dehydration, saline supplementation is sufficient for less severe patients, while in case of more severe sodium loss, i.e., serum sodium is less than 125 mmol/L, 3% to 5% sodium chloride injection can be supplemented. While replenishing fluids to treat dehydration, attention should also be paid to correcting electrolyte and acid-base balance disorders. In the clinical found dehydration symptoms, in addition to rehydration of symptomatic treatment, but also need to address the cause of the treatment. Treatment is mainly to replenish water and electrolytes, mild can be oral rehydration, serious need intravenous rehydration to prevent the occurrence of shock. After the discovery of suspected dehydration, it is recommended to consult the hospital as soon as possible, after a clear diagnosis, follow the doctor’s instructions to standardize the treatment.