How long does oral rehydration therapy take to work for dehydration?

The solution supplies water together with salts and glucose, helping the intestine absorb fluid more effectively than plain water alone. Thirst, a dry mouth, headache, darker urine, or light-headedness may ease as hydration improves. Ongoing vomiting, diarrhoea, sweating, fever, or limited drinking can slow progress. Feeling better does not always mean the fluid deficit has fully corrected.

Mix the sachet exactly as directed with safe water; an overly concentrated mixture can be harmful. Take frequent small sips, especially if nausea is present, and continue replacing fluids after each episode of vomiting or diarrhoea. Rest, avoid alcohol, and pause strenuous activity. Monitor urine colour, alertness, thirst, and ability to keep fluids down. Children, older adults, and people with kidney or heart conditions may need individual advice.

Seek urgent medical help for confusion, fainting, unusual sleepiness, severe weakness, very little or no urine, inability to keep any fluid down, rapid breathing, or worsening symptoms. Get medical advice when dehydration follows persistent fluid loss or when improvement does not start after several hours of careful sipping. Severe dehydration may require fluids through a vein rather than oral treatment.

Ask which solution and amount suit your age, symptoms, medicines, and health conditions. Discuss whether vomiting, diarrhoea, heat exposure, or another cause needs treatment, and what signs should prompt an immediate return for care.