How do oral rehydration salts work?

The precise mix of glucose and salts matches what the gut absorbs best — the glucose actively helps pull water and sodium into the body. That is why ORS rehydrates faster and more completely than water alone during diarrhoea.

How do I use ORS sachets?

Dissolve a sachet in the exact amount of water stated — never stronger or weaker — and sip frequently. After each loose stool or vomit, take more as directed. For children, follow the pack's age guidance or a pharmacist's advice.

Can I make my own rehydration drink?

Pharmacy sachets are strongly preferred because the proportions matter — too much salt or sugar can make things worse, especially for children. Sachets are cheap, accurate and widely available.

Who benefits most from ORS?

Young children, older people, and anyone with heavy or prolonged diarrhoea and vomiting — the groups who dehydrate fastest. For mild cases in healthy adults, water and normal drinks taken little and often may be enough.

Oral rehydration salts | HealthAnswers

Quick answer

What is oral rehydration salts used for?

Oral rehydration salts (ORS) are sachets of glucose and salts dissolved in water to replace fluids lost through diarrhoea and vomiting. They rehydrate more effectively than water alone and are especially useful for children, older people and anyone with heavy fluid loss.

What are oral rehydration salts?

Oral rehydration salts (ORS) are pharmacy sachets containing a precise blend of glucose and essential salts. Dissolved in water, they replace what diarrhoea and vomiting strip out — not just fluid, but the sodium, potassium and glucose the body needs to hold onto that fluid. It is a simple treatment with a remarkable record: globally, ORS has saved millions of lives.

Why not just water?

Water alone replaces volume but not salts, and during diarrhoea the gut absorbs plain water poorly. The glucose in ORS actively transports sodium — and with it water — into the body, so rehydration is faster and more complete. That difference matters most in young children, older people and anyone losing a lot of fluid.

Using them properly

dissolve each sachet in the exact amount of water stated — never stronger, never weaker
sip frequently rather than gulping
take more after each loose stool or vomit, as the pack directs
for children, follow the age-specific guidance or ask a pharmacist

Avoid improvising home mixes: the proportions are the point, and getting them wrong — particularly too much salt or sugar — can do harm, especially in children.

Keep watching for dehydration

ORS supports recovery but does not replace vigilance. Contact a GP or 111 if fluids will not stay down, urine is dark and scarce (or nappies stay dry), drowsiness or dizziness develops, there is blood in the diarrhoea, or things are not improving within a few days — and act sooner for babies, frail older people and anyone with a weakened immune system.

Common questions

How do oral rehydration salts work?: The precise mix of glucose and salts matches what the gut absorbs best — the glucose actively helps pull water and sodium into the body. That is why ORS rehydrates faster and more completely than water alone during diarrhoea.
How do I use ORS sachets?: Dissolve a sachet in the exact amount of water stated — never stronger or weaker — and sip frequently. After each loose stool or vomit, take more as directed. For children, follow the pack's age guidance or a pharmacist's advice.
Can I make my own rehydration drink?: Pharmacy sachets are strongly preferred because the proportions matter — too much salt or sugar can make things worse, especially for children. Sachets are cheap, accurate and widely available.
Who benefits most from ORS?: Young children, older people, and anyone with heavy or prolonged diarrhoea and vomiting — the groups who dehydrate fastest. For mild cases in healthy adults, water and normal drinks taken little and often may be enough.

Sources

NHS — Diarrhoea and vomiting