Teething and Diarrhoea: Is There Really a Connection?

If your baby develops loose nappies just as a tooth seems to be coming through, it can feel natural to connect the two. Teething and diarrhoea often get mentioned together by parents, but NHS guidance is clear: there is no evidence that teething causes diarrhoea.

A baby can certainly have diarrhoea while they are teething. The important difference is that the diarrhoea should not automatically be explained by the tooth. Babies can pick up stomach infections and develop diarrhoea for other reasons during the same period that they are teething.

That means it is worth treating diarrhoea as a separate symptom, particularly if your baby seems unwell, is vomiting, has a fever, is feeding less than usual or is showing signs of dehydration.

Does teething cause diarrhoea?

According to the NHS, there is no evidence that teething causes diarrhoea.

Typical teething symptoms are different. The NHS lists signs such as:

A sore, red gum where a tooth is coming through
One flushed cheek
Increased dribbling
Chewing and gnawing
Ear rubbing
A facial rash
Greater fretfulness
Poorer sleep
A slightly raised temperature below 38°C

Diarrhoea is not included as a normal teething symptom.

If your baby has loose or watery stools while teething, there may be another explanation.

Why do parents associate diarrhoea with teething?

The timing can be convincing.

Most babies start teething at around 6 months, although some begin earlier or later. This is also a period when babies are growing quickly, exploring their surroundings and putting their hands and objects into their mouths.

Babies can therefore be teething at the same time that they develop an unrelated infection or digestive upset.

Once a tooth is visibly coming through, it is understandable to connect every new symptom with it. But two things happening together does not necessarily mean one caused the other.

This matters because assuming diarrhoea is “just teething” could delay recognising that a baby is unwell.

What counts as diarrhoea in a baby?

Baby nappies vary considerably, particularly depending on how a baby is fed.

Breastfed babies often naturally have softer stools, so a loose-looking nappy does not automatically mean diarrhoea.

The NHS describes diarrhoea as passing looser or more frequent stools than is normal for the individual.

The change from your baby’s usual pattern is therefore useful.

You may notice that stools suddenly become much more watery, happen more frequently or look noticeably different from your baby’s normal nappies.

If you are unsure whether what you are seeing counts as diarrhoea, a health visitor, pharmacist, GP or NHS 111 can advise.

What commonly causes diarrhoea in babies?

Diarrhoea in babies and children is commonly associated with gastroenteritis, an infection of the gut.

According to the NHS, diarrhoea and vomiting are common in babies and children and are often caused by a stomach bug.

Other causes are possible too, which is why persistent or concerning diarrhoea should not be self-diagnosed.

The key point for parents is simple: if your baby has diarrhoea during teething, do not assume the tooth is responsible.

Can swallowing extra saliva cause loose stools?

Teething babies often dribble more than usual, and you may hear the suggestion that swallowing extra saliva causes diarrhoea.

This explanation is commonly repeated, but it does not change the NHS advice that there is no evidence teething causes diarrhoea.

If your baby’s stools have become genuinely watery or significantly more frequent, consider diarrhoea separately from their dribbling.

That is particularly important if there are other symptoms of illness.

What if your baby seems well otherwise?

A mild change in a baby’s nappies can happen for many reasons.

If your baby is alert, feeding normally, producing their usual wet nappies and otherwise seems well, you can keep a close eye on them.

Pay attention to whether the stools continue to become more frequent or watery and whether any other symptoms develop.

If you are unsure, asking a pharmacist, health visitor or GP for advice is reasonable. You do not need to wait until your baby seems seriously unwell.

Teething, diarrhoea and fever

A baby who has diarrhoea and a fever should not have both symptoms attributed to teething.

NHS teething guidance says babies may have a slightly raised temperature during teething, but it should remain below 38°C.

The NHS defines 38°C or above as a high temperature or fever.

If your baby has diarrhoea alongside a fever, consider the possibility that they are unwell.

Age is especially important. NHS guidance advises contacting NHS 111 or your GP if a baby under 3 months has a temperature of 38°C or higher. For babies aged 3 to 6 months, a temperature of 39°C or higher also needs urgent medical advice.

Seek advice sooner if your baby seems unwell or you are worried.

Teething, diarrhoea and vomiting

Vomiting alongside diarrhoea is another reason to think beyond teething.

The NHS says diarrhoea and vomiting are commonly caused by a stomach bug and usually stop within several days, although babies need careful observation because they can become dehydrated.

If your baby is repeatedly vomiting, cannot keep fluids down or is feeding much less than usual, seek medical advice.

Very young babies may need assessment sooner.

Why dehydration matters

Babies with diarrhoea can lose fluid quickly.

The NHS lists signs of dehydration that can include:

Fewer wet nappies than usual
Dark yellow, strong-smelling urine
Few or no tears when crying
A dry mouth
Sunken eyes
A sunken soft spot on the baby’s head
Unusual tiredness or irritability

If you think your baby is dehydrated, contact NHS 111 or your GP for advice.

A baby who is unusually drowsy, difficult to wake, breathing quickly or seems seriously unwell needs urgent assessment.

Should you continue feeding a baby with diarrhoea?

NHS guidance for diarrhoea and vomiting advises continuing breastfeeding or bottle feeding.

If your baby is being sick, smaller feeds more often may be advised.

Do not dilute formula.

If you are concerned that your baby is not taking enough milk or is repeatedly vomiting feeds, contact a healthcare professional for advice.

Because feeding advice can depend on your baby’s age and circumstances, seek individual guidance rather than making major changes to their usual feeding routine yourself.

What about oral rehydration solutions?

A pharmacist may recommend oral rehydration powder that is mixed with water if a child is at risk of dehydration.

For babies, particularly very young babies, ask a pharmacist, GP or NHS 111 what is appropriate before giving a rehydration product.

Follow the product instructions exactly.

Do not make your own salt and sugar solution unless a qualified healthcare professional specifically advises you to do so.

Should you give anti-diarrhoea medicine?

Do not give medicines intended to stop diarrhoea to a young child unless a healthcare professional specifically advises it.

NHS guidance says not to give medicine to stop diarrhoea to children under 12.

If you think your baby needs treatment, speak to a pharmacist, GP or NHS 111.

The priority is usually preventing dehydration and identifying whether medical assessment is needed.

Could a change in diet affect nappies?

If your baby has started solid foods, their stools can change in colour, consistency and frequency as they encounter different foods.

A change in nappies after introducing solids is not necessarily diarrhoea.

However, genuinely watery or unusually frequent stools should still be monitored, particularly if your baby seems unwell.

Do not assume that teething is the cause simply because both are happening at the same time.

How to care for sore skin during diarrhoea

Frequent loose stools can irritate the skin around your baby’s bottom.

Change dirty nappies promptly and clean the area gently.

Allowing the skin to dry before putting on a clean nappy can help reduce prolonged contact with moisture.

A barrier cream may be useful for protecting the skin. A pharmacist or health visitor can help you choose an appropriate product if you are unsure.

If the rash becomes severe, spreads, develops blisters or sores, or does not improve, ask a healthcare professional for advice.

Keep an eye on the whole baby

It is easy to focus on nappies when diarrhoea starts, but your baby’s overall condition gives important information too.

Notice whether your baby is:

Alert and responsive
Feeding reasonably normally
Producing wet nappies
Breathing comfortably
Developing a fever
Vomiting repeatedly
Becoming increasingly sleepy or irritable

A baby who is still smiling and interacting but has a couple of unusual nappies is a different situation from a baby who is lethargic, refusing feeds and producing fewer wet nappies.

If you are worried about how your baby looks or behaves, seek advice.

When to get professional advice

Contact NHS 111 or your GP if you are worried about your baby’s diarrhoea, particularly if they are very young, are feeding much less than usual, have fewer wet nappies, seem dehydrated, have blood in their stool, are repeatedly vomiting or seem unusually sleepy or unwell.

The NHS advises urgent medical advice if a baby under 3 months has a temperature of 38°C or higher, or if a baby aged 3 to 6 months has a temperature of 39°C or higher.

Call 999 or go to A&E if your baby has serious warning signs such as severe difficulty breathing, blue, grey, unusually pale or blotchy skin, is difficult to wake or is not responding normally.

Teething and diarrhoea can happen at the same time, but current NHS guidance does not support teething as a cause of diarrhoea. If your baby’s nappies change significantly, particularly alongside other symptoms, it is safer to consider illness rather than assuming a tooth is responsible.