🇪🇺🇺🇸 Kit List Resilience Score
Home / Intel Hub / Medical
Medical · 6 min read

The Rehydration Formula That Stops Fatal Dehydration

When there are no pharmacies, diarrhoea kills through dehydration — especially children. The single most valuable medical skill is making and giving oral rehydration solution correctly.

The quiet killer in a crisis

With no pharmacies and no IV drips, severe diarrhoea — above all in children and the elderly — kills through dehydration, not the illness itself. The most valuable skill in that moment is making and giving an oral rehydration solution (ORS) correctly.

The formula — write it down now

Into 1 litre of clean, boiled-and-cooled water, mix:

  • 6 level teaspoons of sugar
  • ½ level teaspoon of salt

Stir until dissolved. It should taste no saltier than tears — if it tastes like seawater it's wrong and can make things worse; start again with more water. A little mashed banana or a splash of juice adds potassium if you have it.

How to give it

Small, frequent sips — not large gulps: a teaspoon or tablespoon every few minutes for a child, more for an adult. Aim to replace what's lost, roughly a cup after each loose stool. Keep going even if some is vomited: wait ten minutes and resume more slowly. Do not stop fluids to "stop the diarrhoea" — that is the mistake that kills.

When it's an emergency

Sunken eyes, no tears, very little or dark urine, lethargy, or skin that stays "tented" when pinched mean dehydration is severe. Keep giving ORS continuously and seek any help available. Store the written formula inside your first-aid kit — in the moment, you won't want to be recalling ratios.

Test your medical baseline 5 min · ORS, wound care, chronic conditions Build my medical kit 90 sec · items from this guide pre-selected

This guide is published by Systems Fail Lab for general education and preparation. It is not medical, legal, or financial advice. First-aid and medical procedures described here are adapted from published guidance from the World Health Organization (WHO), the International Red Cross and Red Crescent Movement, and the Resuscitation Council, and are intended for situations where professional care is unavailable — always seek qualified medical help when you can. See our full Disclaimer.

Updates & corrections

  • 2026-06-03 — Softened absolute claims; added explicit sources for medical and statistical references.
  • 2026-05-28 — Methodology review; verified primary sources still authoritative.
  • 2026-01-01 — Initial publication.

Spot an error? Email corrections@systemsfaillab.com — we publish corrections, dated.