How does Oral Rehydration Therapy ORT work?

Acute diarrhea normally only lasts a few days. ORT does not stop the diarrhoea, but it replaces the lost fluids and essential salts thus preventing or treating dehydration and reducing the danger. The glucose contained in ORS solution enables the intestine to absorb the fluid and the salts more efficiently. ORT alone is an effective treatment for 90-95% of patients suffering from acute watery diarrhoea, regardless of cause, This makes intravenous drip therapy unnecessary in all but the most severe cases.

Also see Oral Rehydration Therapy: How it Works