Rehidrat is an oral rehydration product — a powder dissolved in water to replace the fluid and salts lost through diarrhoea, vomiting, fever or heavy sweating. It is one of the simplest and most effective things in any pharmacy, and it is especially important for children.
What is Rehidrat?
Rehidrat is sold as sachets of powder made up with water. It does not appear in the South African Medicine Price Registry, which is expected — oral rehydration products are generally sold as general-sale items rather than scheduled medicines.
Read your own sachet for the exact composition and the amount of water to use.
Oral rehydration products of this type work on one of the more elegant pieces of physiology in medicine. During diarrhoea, the gut loses its ability to absorb water on its own. But the glucose–sodium co-transport mechanism keeps working: the gut wall has a pump that carries a sodium ion and a glucose molecule across together, and water follows them by osmosis.
So a solution containing glucose and sodium in the right proportions is absorbed even when plain water is not. Getting the ratio right is what makes it work — which is why the recipe matters and why home substitutes are unreliable.
Standard oral rehydration solutions contain glucose, sodium chloride, potassium chloride and a citrate or bicarbonate to correct the acidosis that accompanies significant fluid loss. Modern formulations are reduced-osmolarity, which works better than the older stronger recipes.
Two things it is worth being clear about:
It is not a treatment for diarrhoea. It does not stop the diarrhoea, shorten it, or kill whatever is causing it. It replaces what is being lost.
That is the point. Most harm from diarrhoea comes from dehydration and salt loss, not from the diarrhoea itself. Oral rehydration therapy is credited with saving tens of millions of lives, mostly children’s, and it does so purely by keeping people hydrated while the illness runs its course.
What is Rehidrat commonly used for?
- Diarrhoea, in children and adults — the main use.
- Vomiting and gastroenteritis, given in small frequent sips.
- Fever, where fluid needs rise.
- Heat exhaustion and heavy sweating.
- After exercise, where losses have been substantial.
- Recovery from illness, where drinking has been poor.
- Travellers’ diarrhoea.
- Preventing dehydration in babies and young children, who dehydrate faster than adults because they are smaller, lose proportionally more fluid, and cannot ask for a drink.
For a child with diarrhoea, this is the treatment. Anti-diarrhoeal medicines such as loperamide are not recommended in children. Rehydration is what matters, and it should be started early — before a child looks unwell — rather than once dehydration has set in.
Two practical points that make a real difference:
Keep feeding. Children with diarrhoea should continue normal feeding, including breastfeeding, alongside rehydration. Withholding food prolongs recovery.
Give it in small, frequent amounts. A few teaspoons or sips every few minutes stays down far better than a glassful, particularly with vomiting.
Who commonly looks for Rehidrat and why
- Parents of a child with diarrhoea or vomiting, which is the most common reason by a wide margin.
- People with gastroenteritis, or recovering from it.
- Travellers, packing for a trip.
- People working or exercising in heat.
- Carers of older adults, who dehydrate easily and often notice thirst less.
- People after a hangover or a bout of vomiting.
- People wondering whether a sports drink or a home mixture would do instead.
That last question deserves a direct answer. Sports drinks are not oral rehydration solution. They contain far more sugar and far less sodium, and the high sugar content can worsen diarrhoea by drawing water into the bowel. They are designed for a different purpose.
Home sugar-and-salt solutions are better than nothing in an emergency, and the World Health Organization publishes a recipe for exactly that reason. But getting the proportions wrong is easy, and too much salt is genuinely dangerous for a small child. If a made-up product is available, use it.
What to check on the label before taking Rehidrat
- How much water each sachet needs, and use exactly that. Do not make it stronger — a concentrated solution is dangerous, particularly for infants — and do not dilute it further.
- Use clean, safe water. Boil and cool it if there is any doubt.
- Mix a fresh batch and discard what is unused after the period stated on the pack, usually 24 hours refrigerated.
- Check the age suitability, and any separate instructions for infants.
- Check the sugar content if you have diabetes.
- Check the sodium and potassium content if you have kidney or heart disease, or are on a restricted diet.
- Do not add anything to it — no sugar, juice, salt or flavouring — as that changes the balance that makes it work.
- Check the expiry date and that sachets are sealed and dry.
Safety, interactions and when to seek professional advice
Made up correctly, oral rehydration solution is very safe. Problems come almost entirely from incorrect mixing, and from using it in place of medical care when medical care is needed.
Speak to a doctor or pharmacist before use if you or the person taking it:
- Has kidney disease, heart failure, or is on a fluid or salt restriction.
- Has diabetes — the glucose content matters, and blood sugars need watching during illness.
- Is on diuretics, ACE inhibitors or other medicines affecting potassium.
- Is an infant under six months, where advice should come from a clinic nurse or doctor.
Get emergency medical help for signs of significant dehydration:
- In a child: sunken eyes, no tears when crying, a sunken soft spot on a baby’s head, very few wet nappies, unusual sleepiness or floppiness, difficulty waking, fast breathing, or refusing to drink.
- In an adult: passing little or very dark urine, dizziness on standing, confusion, a racing heart, or inability to keep any fluid down.
Also seek care urgently for blood or mucus in the stool, persistent vomiting, high fever, severe abdominal pain, a swollen or tender abdomen, or diarrhoea lasting more than two days in an adult or more than a day in a small child. Anyone who is elderly, pregnant, immunosuppressed or has a chronic illness should seek help sooner rather than later.
And a point worth making plainly: rehydration buys time, it does not diagnose. If someone is not improving, keep the fluids going and get them seen.
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Frequently asked questions
What is Rehidrat used for? Replacing fluid and salts lost through diarrhoea, vomiting, fever or heavy sweating, and preventing dehydration — particularly in children.
Does it stop diarrhoea? No. It replaces what is being lost while the illness runs its course. That is what prevents the harm.
Can I use a sports drink instead? Not really. Sports drinks have much more sugar and much less sodium, and the sugar can make diarrhoea worse.
Can I make it stronger so it works better? No. Mixing it too concentrated is dangerous, especially for infants. Use exactly the water stated.
How much should I give a child? Follow the pack, and give small amounts frequently — sips or teaspoons every few minutes work better than a glass at once. Ask a pharmacist or clinic nurse if unsure.
Should my child stop eating? No. Continue normal feeding, including breastfeeding, alongside the rehydration solution.
How long does made-up solution keep? Follow the pack — usually 24 hours refrigerated, then discard it.
When should I see a doctor? For sunken eyes, no tears, few wet nappies, unusual sleepiness or refusal to drink in a child; for blood in the stool, persistent vomiting, high fever or severe abdominal pain at any age.