Diarrhoea in children: when to worry

Posted on 1 March 2022

Stomach upsets can be anything from unpleasant to distressing – but when it’s your child experiencing diarrhoea or vomiting, it can have serious consequences.

Dr Bernard Linde, a paediatrician at Mediclinic Stellenbosch, warns that diarrhoea and vomiting are more dangerous for infants and toddlers. This is because they’re at far greater risk of dehydration and it’s up to their caregivers to interpret their symptoms. In addition, infants’ immature immune systems are ill equipped to fight the infections causing the diarrhoea, he explains. “However, babies younger than six months are most at risk of dehydration, because their bodies haven’t developed to the point where they can handle the significant loss of fluid caused by vomiting or a runny stomach.”

Danger signs

One episode of vomiting might not warrant a trip to the paediatrician – but, says Dr Linde, if your child has diarrhoea as well, and is refusing to take medicine or vomiting up anything you’ve tried to give, this is a serious situation. “If you’re not managing to replace the fluids lost with an appropriate fluid, the risk of dehydration increases,” he cautions. The following are further signs that dehydration might be developing and if any of them are present, see a healthcare provider urgently:

  • Blood in the stool – especially with fever.
  • Severe and worsening cramps.
  • Dry mouth.
  • Sunken fontanelle (soft spot on top, back, and sides of your baby’s head).
  • Sunken eyes.
  • Absence of tears.
  • Unusually fast heart rate or fast breathing.
  • Lethargy (listlessness).
  • Decrease in the number of wet nappies.

What to do

Dr Linde says if diarrhoea is accompanied by vomiting, fever, loss of appetite and listlessness, it’s probably the result of an infection – but the cause may also be non-infectious.

Either way, make an appointment with your paediatrician or GP, especially if the diarrhoea and vomiting has gone on for more than 4-6 hours – and, if the illness strikes at night, don’t hesitate to have your child assessed at the nearest emergency centre. Encourage your child to drink small amounts of commercially available oral rehydration solution, or, if you’re breastfeeding, keep up with your schedule, as breast milk is an ideal fluid for rehydration.

What about eating?

Parents often stress about what their children are eating – or not – during a bout of diarrhoea. But, says Dr Linde, you needn’t worry too much about cutting out certain foods for fear of making the stomach bug worse. “Food isn’t the main priority when you’re trying to manage diarrhoea and vomiting. It’s far more important to ensure your child takes in fluid after every episode, to replace lost fluids and electrolytes.”

However, you may find your child feels nauseous after eating fatty foods, and that juice or other sugary drinks make the diarrhoea worse. Milk has long been believed to worsen the condition but, says Dr Linde, it’s only necessary to avoid dairy products if the diarrhoea persists for two weeks or longer.


In the interest of our patients, in accordance with SA law and our commitment to expertise, Mediclinic cannot subscribe to the practice of online diagnosis. Please consult a medical professional for specific medical advice. If you have any major concerns, please see your doctor for an assessment. If you have any cause for concern, your GP will be able to direct you to the appropriate specialists.