# Oral rehydration > Salt, sugar and water against cholera - Date: 1968 - Era: Modern age - Domain: [Medicine & Hygiene](https://lastcodex.org/en/domains/medicine/) - Rebuild stage: V (Electric age) - Difficulty: 2/5 - URL: https://lastcodex.org/en/inventions/oral-rehydration/ Oral rehydration therapy replaces the water and salts lost in diarrhoea with a drink of clean water, salts and glucose in a fixed balance, which the gut keeps absorbing even during cholera. Proved in trials in Dhaka and Calcutta in 1968 and packed in standard sachets since the 1970s, it is credited with saving tens of millions of children. ![Oral rehydration · Salt, sugar and water against cholera](https://lastcodex.org/_astro/plate.D2Qf-bor_stHlN.webp) ## Legend 1. Cholera cot with its bucket 2. Sachet of oral rehydration salts 3. Jug of safe water 4. Cup and spoon 5. Villi of the small intestine 6. Sodium–glucose transporter in a lining cell ## What it is Diarrhoea kills by drying the body out. In cholera, a toxin makes the lining of the small intestine pour water and salts into the gut, and an adult can lose litres of watery stool within hours. The blood volume falls, the kidneys fail, and without treatment death can follow the same day. Most diarrhoea in children is milder, caused by viruses or other bacteria, but it still kills hundreds of thousands of them a year. Oral rehydration therapy replaces those losses by mouth. The patient drinks a solution of clean water, common salt, glucose, potassium and citrate, mixed from a sachet of oral rehydration salts (ORS). It does not stop the diarrhoea; it keeps the patient alive while the body clears the infection. The plate shows a cholera camp in Bengal in the early 1970s. A child lies on a cholera cot, whose hole and bucket let nurses measure every loss, while his mother gives the drink by cup. On the right, a section of the gut lining shows why it works. ## How it works The small intestine is lined with villi, tiny finger-like folds covered by a single layer of cells. Each cell carries in its outer membrane a protein that moves sodium and glucose into the cell together: two sodium ions for every molecule of glucose. Robert Crane proposed this coupling in Prague in 1960, and experiments on rabbit gut in 1964 confirmed that sugar drives sodium absorption. Chloride follows the sodium, and water follows the dissolved salts and sugar. The cholera toxin drives secretion but leaves this transporter working. A drink with both sodium and glucose is therefore absorbed even while the gut is losing fluid, and enough of it keeps pace with the losses. Plain water brings no salt, so on its own it cannot replace what is lost, and in large amounts it dilutes the sodium left in the blood. Sweet drinks such as sodas or fruit juice contain too much sugar and too little salt. The excess sugar stays in the gut and draws water into it, which makes the diarrhoea worse. The low-osmolarity formula recommended by WHO in the early 2000s holds less sodium and glucose than the first solution. In children with diarrhoea other than cholera, it cut stool volume by a fifth to a quarter, depending on the study, and unplanned drips by about a third. ## How it is made and used This section describes how health systems supply ORS and teach its use. It is not a home recipe. ![Two hands pouring the powder of an opened sachet into a glass jug of water, with a spoon beside it](https://lastcodex.org/_astro/v2.DklfBOW9_Z2rFhvp.webp) _A health worker shows a mother how to empty the whole sachet into the volume of safe water printed on it._ **Industrial sachets.** Pharmaceutical plants mix purified glucose, sodium chloride, potassium chloride and trisodium citrate to the WHO formula and seal the dry powder in moisture-proof foil, each sachet sized for a stated volume of water. In 2024 UNICEF alone delivered 29.2 million sachets to 56 countries, often packed with zinc tablets, for well under one US dollar a course. **Teaching families.** At a clinic or a home visit, a health worker shows the parent how to dissolve one sachet in the exact volume of safe water printed on it, boiled and cooled if the source is doubtful. The solution is given in small, frequent sips from a cup or spoon, more slowly if the child vomits, and any left after a day is thrown away. Breastfeeding and normal meals continue throughout. WHO also recommends a 10–14 day course of zinc for children with diarrhoea, which shortens episodes and lowers the chance of another soon after. ![A hand pinching a fold of skin on the belly of a lying infant](https://lastcodex.org/_astro/v1.CoQYRPsI_Z1fjNOO.webp) _A skin fold that takes two seconds or more to go back is one sign of severe dehydration._ **Recognising dehydration.** Health workers look for restlessness, sunken eyes and eager thirst, which mean some dehydration. A child with at least two of the following is severely dehydrated: lethargy or unconsciousness, sunken eyes, being unable to drink or drinking poorly, and pinched skin that goes back very slowly. Such patients, and anyone in shock, receive intravenous fluids in a health facility first, then continue with ORS. **When to seek care at once.** Parents are taught to return immediately if the child becomes drowsy, cannot drink, keeps vomiting, passes blood in the stool, passes no urine for many hours, or does not improve. Very young babies and malnourished children need a health worker from the start. > **Safety.** Use ready-made ORS packets, dissolved in exactly the volume of safe water printed on them. Too much powder makes the solution dangerous, and too much water makes it less effective. If no packet is at hand, keep giving safe water, broth or breast milk, avoid very sweet drinks, and seek care. ORS does not replace medical care: dehydration can kill a small child within hours, so anyone with danger signs must be taken to a health facility without delay. ## History and evolution In 1832, in Leith near Edinburgh, Thomas Latta followed a suggestion by William O'Shaughnessy and injected salt water into the veins of dying patients. Some revived, but Latta died the next year, and the method was neglected for half a century. ![A nineteenth-century brass syringe with a flexible tube ending in a fine cannula, a basin of water and a folded cloth](https://lastcodex.org/_astro/v3.wOSTR1gv_Z12YXC1.webp) _Latta's injections needed a syringe, a vein and a doctor at the bedside._ By the 1960s intravenous saline, refined by the US Navy doctor Robert Phillips, brought cholera deaths below 1%, but it needed sterile fluid, needles and trained staff. Researchers in Dhaka, then in East Pakistan, and at a Johns Hopkins centre in Calcutta tested glucose and salt by mouth. In 1968 Norbert Hirschhorn showed that glucose cut net stool loss, and David Nalin and Richard Cash reported that patients given the drink needed 80% less intravenous fluid. The plate takes 1968 as its date. During the 1971 war, cholera broke out among refugees from East Pakistan near Bongaon, in India. With intravenous fluid short, Dilip Mahalanabis's team kept drips for the most severe cases and treated the rest by mouth. Of 3,703 patients admitted to their centre, 3.6% died, while early in the outbreak cholera had killed close to 30% of its victims. The report appeared only in 1973. WHO and UNICEF agreed on a single formula in 1975, and in 1978 The Lancet called the discovery "potentially the most important medical advance this century". From 1980 to 1990 the Bangladeshi organisation BRAC sent workers door to door to teach more than 12 million mothers a home drink of salt and raw sugar. WHO recommended a lower-osmolarity formula in the early 2000s, and a joint statement with UNICEF in 2004 promoted it together with zinc. Estimates of the children saved run from more than 50 million between 1982 and 2007 to over 70 million by 2019, though clean water, sanitation and vaccines also played a part. ## Key figures - Nalin and Cash's trial: The Lancet, August 1968: 80% less intravenous fluid needed - Bongaon treatment centre, 1971: 3.6% of 3,703 cholera patients died, against close to 30% early in the outbreak - WHO low-osmolarity formula: 245 mOsm/L, against 311 for the original solution - Diarrhoea deaths under age five: About 444,000 a year (WHO, 2024) - Children saved, 1982–2007: More than 50 million (Fontaine, Garner and Bhan estimate) ## Requires - [Drinking Water](https://lastcodex.org/en/inventions/drinking-water/): Draw, settle, filter, boil (c. 8,400 BCE) - [Measures and standards](https://lastcodex.org/en/inventions/measures-and-standards/): The cubit, the balance and the metre (c. 3,000 BCE) ## Sources - [Diarrhoeal disease (fact sheet, 7 March 2024)](https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease), World Health Organization - [Cholera (fact sheet)](https://www.who.int/news-room/fact-sheets/detail/cholera), World Health Organization - [Clinical management of acute diarrhoea: WHO/UNICEF joint statement (2004)](https://www.who.int/publications/i/item/WHO_FCH_CAH_04.7), World Health Organization - [Oral rehydration salts (ORS) and zinc](https://www.unicef.org/supply/oral-rehydration-salts-ors-and-zinc), UNICEF Supply Division - [Zinc and ORS (S. Singh, 2007)](https://www.pediatriconcall.com/pediatric-journal/view/fulltext-articles/165/J/0/0/251/0), Pediatric Oncall Journal, vol. 4 no. 1 - [Robert K. Crane: Na+-glucose cotransporter to cure? (K. L. Hamilton, 2013)](https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2013.00053/full), Frontiers in Physiology - [Oral rehydration therapy: a low-tech solution that has saved millions of lives](https://ourworldindata.org/oral-rehydration-therapy), Our World in Data - [Magic bullet: the history of oral rehydration therapy (J. N. Ruxin, 1994)](https://pmc.ncbi.nlm.nih.gov/articles/PMC1036912/), Medical History, vol. 38 no. 4 - [Leith in the time of cholera: the story of Thomas Latta (G. A. Venters)](https://hekint.org/2017/02/01/leith-in-the-time-of-cholera-the-story-of-thomas-latta/), Hektoen International - [Treatment of cholera: Robert Allan Phillips (1967 Clinical Medical Research Award)](https://laskerfoundation.org/winners/treatment-of-cholera/), Lasker Foundation - [A simple solution: the history of ORS in Bangladesh](https://theworld.org/stories/2013/06/25/simple-solution-history-ors-bangladesh), The World (PRX) - [Oral fluid therapy of cholera among Bangladesh refugees (Mahalanabis et al., 1973)](https://pure.johnshopkins.edu/en/publications/oral-fluid-therapy-of-cholera-among-bangladesh-refugees-5/), Johns Hopkins Medical Journal, vol. 132 no. 4 - [Intestinal ion transport and the pathophysiology of diarrhea (M. Field, 2003)](https://www.jci.org/articles/view/18326), Journal of Clinical Investigation, vol. 111 no. 7 - [Active glucose transport 2020 and beyond (E. M. Wright and D. D. F. Loo, 2021)](https://doi.org/10.1093/function/zqaa047), Function, vol. 2 no. 1 - [Treating cholera](https://www.cdc.gov/cholera/treatment/), Centers for Disease Control and Prevention Fact-checked on 2026-10-14. --- The Last Codex · https://lastcodex.org/en/inventions/oral-rehydration/ · © The Last Codex. Texts, plates and figures: CC BY-NC-ND 4.0.