Oral Rehydration Therapy

Oral rehydration therapy is promoted by the World Health Organization to reduce the number of deaths caused by dehydration due to diarrhoea.

What is oral rehydration therapy?

Oral rehydration therapy is the administration of fluid by mouth to prevent or correct dehydration. Dehydration is the loss of water and dissolved salts from the body. Rehydration is the correction of dehydration. Oral rehydration solution is the solution used in oral rehydration therapy.

What happens when you have Diarrhoeal diseases (Purging)?

Diarrhoeal diseases cause your body to lose water and electrolytes (salt) Loss of water will lead to dehydration while loss of electrolytes will lead to some of the normal body functions not working as it should. Loss of electrolytes could also cause the water to leave the blood vessels. The combination of these can lead to shock and death if not treated.

Importance of oral rehydration therapy

  • Prevent dehydration
  • Restore lost electrolytes (dissolved salts)

Viral gastroenteritis (stomach virus) is an intestinal infection whose symptoms include diarrhoea, stomach pain, nausea and/or vomiting. Viral gastroenteritis (stomach virus)will stop on their own and most diarrhoea diseases of viral origin will stop by 3 to 4 days.  Management is therefore aimed at preventing the effect of diarrhoea. Stomach virus oral rehydration therapy helps prevent dehydration, helps rehydrate and restore lost electrolytes (dissolved salts).

Oral rehydration solution contains water which replaces the water lost. The sugar in the solution also helps the intestines absorb salt and as water follows sodium (salt), water will be absorbed into the body and further resolve dehydration. When someone is having diarrhoea, their intestine’s do not absorb salt and water as it should. It can however still use glucose (sugar) to help absorb salt and water.

Oral rehydration therapy guidelines

WHO oral rehydration solution recipe

ComponentOriginal ORS (grams/liter)Reduced osmolarity ORS
(grams/liter)
anhydrous glucose2013.5
Sodium chloride3.52.6
Potassium chloride1.51.5
Trisodium citrate dihydrate2.92.9
Table shows WHO and UNICEF’s oral rehydration solution formulation

How to use sachet oral replacement solution

  • Pour the content of the oral powder into 200 mL of water.
  • Stir properly until all the powder has dissolved.
  • Ensure the full dose is completed.
oral rehydration therapy
Picture shows how to use oral rehydration therapy credit: olllikeballoon/shutterstock

Ingredients for home-made oral rehydration solution

  • Water
  • Sugar
  • salt
  • Banana or orange juice

How to make home-made oral rehydration solution

  • Take 6 level teaspoons of sugar
  • with 1/2 level teaspoon of salt
  • and dissolve in 1 litre of water

For the addition of potassium and to improve taste, add 1/2 cup of orange juice or mashed banana.

How much ORS should I give?

  • Give 10mls/kg of body weight every hour for 4 to 6 hours. This means that the child gets 10 x (child’s weight in kg) every hour in the first 4 to 6 hours.
  • Example, if the child weighs 15kg, the child will have 10 x 15 =150ml every hour for the first 4 to 6 hours.
  • After the first 4 to 6 hours, the child should be given 10 x (child’s weight in kg) after every diarrhoea episode or vomiting.

Storage of ORS after mixing in water

Oral rehydration salts mixed with water can be used up to one hour if stored at room temperature or up to 24 hours if stored in the fridge.

What if my child is sick (vomits)?

Most times, diarrhoea and vomiting happen at the same time when you have a stomach virus. If the child vomits, then give regular small amounts (about 10-20mls) every 5-10 minutes as taking a lot at a time may make the patient sick. It is still important that the patient still finishes the full content.

When to see the doctor

If your child is unable to take any fluids.

If your child cannot keep down any fluids and/or are showing signs of dehydration.

If your child’s diarrhoea is getting worse and not better after 48 hours.

Use of antibiotics

Routine use of antibiotics to treat diarrhoea is not recommended. This is because most diarrhoea is caused by viruses and antibiotics cannot cure a virus. In fact, it can worsen the situation as it can disrupt the normal flora of the gut.

The gut contains between 10 trillion to 100 trillion bacteria and other microorganisms that help us to synthesize(produce) vitamins, metabolize (convert) drugs and fight pathogens (infectious agents). Antibiotics disrupt the balance of microorganisms as it kills both “good” and “bad” bacteria thereby giving the diarrhoea causing the virus to multiply more and worsen the disease.

About the author

Author profile

Nwasom is a pharmacy graduate and a pharmacist currently practising in the United Kingdom. I have great experience communicating with patients and their family as gained through working as a pharmacist in both the hospital and community pharmacy sector. I love writing so it was a natural thing to try and pass medical and health information on through writing.