Mix oral rehydration salts

Diarrhoeal illness kills by dehydration, not by infection. That is the whole insight behind this page: in the overwhelming majority of cases, the thing that kills is fluid loss, and fluid loss is treatable with sugar, salt and clean water.

Oral rehydration therapy is credited with saving tens of millions of lives since it came into widespread use, and it is one of the very few genuinely high-impact medical interventions that a household can perform with kitchen ingredients.

In an emergency with poor sanitation and uncertain water, gastrointestinal illness is close to inevitable. This is the page that matters when it arrives.

Why this matters so much

Under the conditions this app is written for, the ordinary background risks change:

• Water supply is uncertain, so contamination is likelier.
• Sanitation is degraded, so faecal-oral transmission is likelier.
• Handwashing may be rationed.
• People are eating stored, preserved and improvised food.
• Medical help may be hours or days away, or unavailable.

A child with severe diarrhoea can become dangerously dehydrated within hours. Small bodies have small reserves. That is the scenario this page exists for.

The recipe

Level teaspoons, not heaped. The ratio matters, and it is the one place in this page to be precise.

Use clean water. Boiled and cooled, or filtered and disinfected. See the water domain. Making up rehydration solution with contaminated water gives the patient another dose of what is already making them ill.

Sachets are better if you have them. Commercial oral rehydration salts contain potassium and citrate as well, which the kitchen version does not. They are cheap, they store for years, they weigh nothing, and they are one of the highest-value items you can put in a first aid kit. Stock them. The kitchen recipe is what you use when they run out.

What not to use instead:

• Plain water alone does not replace the salts being lost, and in large volumes can dilute blood sodium dangerously.
• Fizzy drinks, undiluted fruit juice and sports drinks are far too sugary. The excess sugar draws water into the gut and makes diarrhoea worse. If it is genuinely all you have, dilute it heavily, at least one part juice to five parts water, and add a pinch of salt.
• Milk is not the right vehicle during acute diarrhoea, with the important exception below.

Why sugar as well as salt

Worth understanding, because it explains why the ratio matters and why plain salt water does not work.

The gut absorbs sodium and glucose together, via a shared transport mechanism, and water follows them across passively. Salt alone is poorly absorbed by an inflamed gut. Glucose alone does nothing for the salt loss. Together, they are actively pulled through the gut wall, and the water comes with them.

That co-transport mechanism keeps working even when the gut is badly inflamed, which is why oral rehydration works in illnesses as severe as cholera. It is one of the more elegant pieces of physiology in medicine and it is available to anyone with a spoon.

Giving it

The technique matters as much as the recipe, because a nauseated child will vomit a large drink straight back.

• Small amounts, very often. A teaspoon or a sip every 1 to 2 minutes. Not a glass.
• Keep going after each episode. Roughly a cup for an adult, or a quarter to half a cup for a child, after each loose stool, in addition to normal drinking.
• If they vomit, wait 10 minutes, then start again more slowly, a teaspoon at a time. Vomiting is not a reason to stop; it is a reason to slow down.
• Use a spoon, a syringe or a cup for a small child. A bottle encourages gulping.
• Keep breastfeeding, alongside the solution, more often than usual. This is the exception to the milk rule and it is important: breast milk is both fluid and nutrition and should not be stopped during diarrhoea.
• Do not stop feeding an older child or adult once they can eat. Resume ordinary food as soon as they will take it. Prolonged starvation prolongs the illness.
• Make fresh daily. Discard any solution over 24 hours old, and keep it covered and cool.

Recognising dehydration

Weigh a small child if you have scales. A drop in body weight during an illness is the most reliable measure of fluid lost, and it is the one objective figure available to you at home.

When this is not enough