Diarrhoea in children: how it runs, what to watch and when a doctor is needed

Diarrhoea is stool that is more frequent and looser than usual. The word “usual” is the key one here: frequent, soft stools are normal for a breastfed baby, while the same picture in a schoolchild means illness. So the benchmark is change compared with what is typical for this particular child.

What is important to watch

• How often the child passes stool and what it looks like — and above all how this changes day by day.
• Whether there is vomiting: vomiting combined with diarrhoea speeds up fluid loss.
• Passing urine: how often and how much.
• The child's activity and behaviour, and their ability to drink.
• Temperature and tummy pain.
• Stool features the doctor should be told about: blood, mucus mixed with blood, black tarry stools.

How long it lasts

With an ordinary viral gut infection, stools return to normal within a few days, sometimes up to a week, and full recovery of the usual consistency can take a little longer. Diarrhoea that drags on beyond a week, returns in waves, or comes with weight loss is a reason for an examination and a discussion of other causes.

Age and risk

The younger the child, the smaller their fluid reserve and the faster dehydration sets in. In babies under one year, frequent watery stools together with a high fever or vomiting call for closer monitoring and an earlier visit to the doctor. The signs of fluid loss are covered in detail in a separate article — see the link below.

Fluids: the main direction of help

• Give drinks more often than usual, in small amounts — this is tolerated better, especially if there is vomiting.
• Oral rehydration solutions are used to replace losses; the right solution and amount are best confirmed with a doctor or a pharmacist.
• Homemade salt solutions are not recommended: a mistake in the recipe makes them unsafe.
• Breastfeeding continues; the baby is put to the breast more often.

Is a special diet needed

Prolonged strict food restrictions are not needed for ordinary childhood diarrhoea and they hinder recovery. The child returns to their usual age-appropriate food as soon as they are ready to eat, and the amount and composition are guided by their own appetite.

Specific lists of “allowed” and “forbidden” foods are deliberately not given here: they circulate on the internet, contradict one another and have no convincing basis. If the child has dietary peculiarities, an allergy or a chronic illness, their food during the illness is discussed with a doctor.

When an examination is needed

• there are signs of dehydration, or the child refuses to drink;
• the stool contains blood, mucus mixed with blood, or is black and tarry;
• the child is listless and hard to wake;
• severe tummy pain, or a swollen, tender abdomen;
• a baby under one year with frequent watery stools and a high fever;
• diarrhoea lasting more than a week, returning in waves, or accompanied by weight loss.

This page is for general information only and is not a substitute for a consultation with a doctor. A child's diagnosis and treatment are determined by a doctor during an examination.