You may have seen this scenario play out: an infant’s or toddler’s pacifier falls out of his mouth and onto the floor.  The mother (I’ve never seen a father do this) picks it up and sticks it in her mouth to clean it, then plugs the baby’s mouth with the newly-cleaned pacifier.  This happens without the slightest hesitation or doubt on the mother’s part.  If you think this is gross or somehow is dangerous to the baby, get over the yuck factor and think again:

Parental sucking of their infant’s pacifier may reduce the risk of allergy development, possibly via immune stimulation by microbes transferred to the infant via the parent’s saliva.


That’s right.  Mothers who cleaned the fallen pacifier protected their children from developing allergic diseases such as asthma and eczema!  They were also less likely to test positive for common environmental allergens that can trigger asthma, eczema, and allergic rhinitis:

The different allergens tested for kids’ sensitivity to them included birch, timothy grass, mugwort, cat, dog, horse, mold, house dust mites, milk, egg, soy, fish, wheat and peanut.


This seems to be another study that supports the “hygiene hypothesis,” which proposes that living in a dirty environment (with lots of commensal or “good” bacteria hanging around) stimulates a young human’s immune system in such a way as to protect them from developing allergic and inflammatory conditions.  So while you probably shouldn’t be rubbing dirt into your young athlete’s cut (tetanus notwithstanding, THAT would be an interesting study!), keeping your toothbrush after a strep throat and cleaning a pacifier with your own mouth, today at least, makes a little bit of sense.

Read study in Pediatrics here.

Read study review at here.


(Image: Carlos Porto/