Diarrhoea in a newborn: what to know

Breastfed babies often have soft or runny yellow stools, and stool frequency can vary. Formula-fed babies may have thicker stools. Diarrhoea is more concerning when stools become noticeably more watery or frequent than the baby's usual pattern, especially with mucus, blood, fever or vomiting.

A newborn has limited fluid reserves. Dehydration may show as fewer wet nappies, a dry mouth, no tears when crying, unusual sleepiness, a sunken soft spot or difficulty waking for feeds. These signs should be assessed urgently rather than managed with drinks or medicines at home.

Keep offering breastfeeds or the usual formula feeds unless a clinician tells you to pause. Do not dilute formula, give plain water, or use homemade rehydration mixtures. Record feeds, wet nappies, stool appearance, vomiting and temperature; a photo of an unusual nappy can help the clinician.

Wash hands carefully after every nappy change and clean feeding equipment as advised. Do not give anti-diarrhoeal medicine, antibiotics or herbal products without a newborn clinician's instruction.

Seek urgent care for a newborn with a fever, blood in the stool, repeated vomiting, a swollen abdomen, breathing difficulty, marked sleepiness, refusal of feeds, or clearly reduced urination. Contact a paediatric clinician promptly for repeated watery stools or any sudden change that concerns you. A baby who is hard to wake, floppy or showing dehydration needs emergency assessment.

Ask how your baby's normal stools should look, whether feeding should change, how many wet nappies are expected for your baby, and whether the stool needs testing for gastroenteritis or food intolerance.