Can teething cause diarrhea?

The AAP's official position is that teething does not cause diarrhea or fever. Multiple studies, including a systematic review in the journal Pediatrics, found no causal link between teething and loose stools. What the research does show is that teething babies experience more drooling and gum discomfort — but not genuine diarrhea. When loose stools appear during teething, there's usually a separate explanation: a stomach bug, a reaction to a new food, or just coincidental timing.

Why does my baby get loose poop every time they teethe?

The timing feels causal but is mostly coincidental. Teething starts around 4-8 months — the same window when babies are losing maternal antibodies (their first immune dip), being introduced to solid foods, and putting everything in their mouths (more bacteria exposure). Stomach bugs and dietary reactions are common at this age for those reasons, and they overlap with teething. The other factor: increased drool. Babies swallow extra saliva during teething, which can slightly soften stools in some babies.

Does swallowing drool change poop?

Possibly in a minor way. Saliva contains digestive enzymes, and swallowing significantly more saliva than usual (which teething babies do) may slightly speed up digestion in some babies. This can produce slightly looser or more frequent stools. But this is a mild effect — not the diarrhea-level loose stools many parents attribute to teething. If stools are genuinely watery and frequent, look for another cause.

Can teething cause green poop?

Teething itself doesn't directly cause green poop. But the chain of events that comes with teething can: increased drool swallowing, faster gut transit, a mild stomach bug picked up from mouthing objects, or a new food introduced around the same time. Any of these can produce greener stools. If green poop also comes with mucus, fever, or significant fussiness beyond what you'd expect from gum soreness, treat it as a separate issue worth calling about.

How do I know if loose poop is from teething or something else?

Look for other symptoms. Teething legitimately causes drooling, gum swelling, irritability, and sometimes a low-grade temperature under 100.4°F. If your baby has loose stools plus fever over 100.4°F, vomiting, visible blood or mucus in the stool, or the diarrhea lasts more than 2 days, teething isn't the explanation. That's a stomach bug or another illness that needs attention regardless of whether teeth are coming in.

Does Teething Change Baby's Poop? The Real Answer

The moment a teething baby gets loose poop, most parents assume the two are connected. It makes intuitive sense — something's happening in the body, and the digestive system reacts.

The evidence, though, doesn't support the connection the way most people think it does.

What the AAP actually says

The American Academy of Pediatrics is clear: teething does not cause fever above 100.4°F (38°C) or diarrhea. The symptoms it does cause are local — drooling, gum swelling, irritability, and sometimes a mild temperature that stays below 100.4°F. Anything beyond that isn't teething.

This position is backed by research. A systematic review published in Pediatrics looked at multiple studies examining the symptoms associated with teething. The finding: gum inflammation and drooling were consistently linked to tooth eruption. Diarrhea and high fever were not.

So why does it seem like teething causes poop changes?

Because the timing is almost perfectly designed to look causal when it isn't.

Teething typically starts between 4 and 8 months. In that same window:

Babies are losing the maternal antibodies they were born with — their first immune dip, making stomach bugs more likely
Solid foods are being introduced, and every new food is a potential GI disruption
Babies are mouthing everything, which means they're picking up more bacteria and viruses from their environment

All of those things independently cause loose stools and poop changes. They just happen at the same age as teething, so teething gets the blame.

The drool factor (real, but limited)

There is one legitimate pathway between teething and poop: drool.

Teething babies produce significantly more saliva. They swallow most of it. Saliva contains digestive enzymes and can slightly accelerate gut transit when swallowed in large amounts. For some babies, this produces mildly looser stools during periods of heavy drooling.

This is a real effect, but it's mild. It doesn't produce genuine watery diarrhea. If that's what you're seeing, there's something else going on.

What to actually watch for

Some poop changes during teething are worth tracking separately from teething itself:

Looseness that goes beyond "a little softer"

Watery or mucusy diarrhea, especially if it happens more than 3-4 times in a day, isn't a teething symptom. It's more likely a stomach bug or a reaction to a new food.

Green poop with mucus

Green poop alone can happen from faster transit (including from drool swallowing). Green poop with visible mucus suggests something is irritating the gut lining — an infection or allergy is more likely than teething.

Any blood in the stool

Blood doesn't come from teething. Full stop. A small streak of bright red blood can come from a minor anal fissure. Blood mixed throughout the stool needs a call to your pediatrician.

Fever over 100.4°F

A temperature above 100.4°F is not a teething symptom, regardless of how confident someone seems when they tell you it is. A baby with loose stools and that level of fever has a sick baby, not a teething baby.

When to call your pediatrician

Fever over 100.4°F (38°C)
Diarrhea that lasts more than 48 hours
Blood or significant mucus in the stool
Baby seems lethargic, not just fussy
Fewer wet diapers than usual (dehydration sign)
Vomiting alongside the loose stools

If your baby has loose stools without any of those, keep them comfortable, make sure they're drinking well, and give it a day or two. It's probably a passing stomach bug that coincided with a tooth coming in — not teething itself.

Tracking across the teething months

The teething period tends to last months, with teeth arriving in waves. If you're not sure whether a digestive pattern is related to teething, diet, or something recurring, PipPoopie's diaper log lets you track stool changes over time alongside what baby's been eating. After a few cycles, you'll see whether the loose poop correlates with new foods or just seems to appear randomly — which tells you a lot about whether it's truly digestive or something else worth investigating.