Oral rehydration solutions

What are oral rehydration solutions?


Oral rehydration solutions (ORS) are used to treat dehydration caused by diarrhea, a common illness in travellers. Unlike other fluids, the ratio of the ingredients in an ORS matches what the body needs to recover from a diarrheal illness.

An ORS contains three ingredients:

  1. Clean water that has been boiled or disinfected or from a commercially sealed bottle.
  2. Electrolytes (also called “salts”), which are chemicals that your body needs to function properly.
  3. Carbohydrates, usually in the form of sugar.

How and when should an oral rehydration solution be used?

  • It is essential to drink extra fluids as soon as diarrhea starts.
  • Most healthy adults with uncomplicated travellers’ diarrhea can stay hydrated without ORS by drinking purified water, clear soups, or diluted juices or sports drinks. Although it may not be necessary, healthy adults with mild diarrhea can also use ORS.
  • Dehydration from diarrhea is more of a concern in children, those with underlying medical conditions, and the elderly. ORS should be considered for these individuals.
  • Fluids should be consumed at a rate to satisfy thirst and maintain pale-coloured urine.
  • Instructions for preparing the oral rehydration solution and dosage should be followed carefully. The World Health Organization recommends drinking the following amounts of ORS during a diarrheal illness:
Children under 2 years 50–100 mL (¼ to ½ cup) after each episode of diarrhea
Children 2 to 9 years 100–200 mL (½ to 1 cup) after each episode of diarrhea
Persons 10 years or older As much as wanted, up to approximately 2L (8½ cups) a day
  • Infants should continue to receive breast milk or their usual formula in addition to ORS. Children who are no longer nursing and adults should continue to eat solid food in addition to ORS.
  • Avoid alcohol, caffeinated or sugary drinks like coffee, energy drinks, pop, sweetened fruit juices, and tea. Alcohol and caffeine can worsen dehydration and sugary drinks can worsen diarrhea.
  • Seek medical attention if the diarrhea is bloody, is accompanied by a high fever, jaundice (yellow skin), or persistent vomiting, or if dehydration or diarrhea does not improve despite the use of ORS.

Preparing oral rehydration solutions

  • Use commercially-available oral rehydration salts. Homemade versions of ORS are not recommended to treat dehydration. These should only be used to help prevent or delay the onset of dehydration on the way to seeking medical attention when commercial oral rehydration salts are not available.
  • Mixing commercially-available oral rehydration salts with water produces an oral rehydration solution. Instructions for preparing the ORS and dosage should be followed carefully. Always use boiled or treated water to prepare the ORS.
  • Packets of oral rehydration salts are available in pharmacies in most countries, although it is recommended to purchase them before leaving Canada and include them in your travel health kit.
  • Once prepared, ORS should be consumed or discarded within 12 hours if kept at room temperature or 24 hours if kept refrigerated.
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