Scientists Swallowed Legos. Here's What Parents Need To Know

How long does it take to digest a Lego? Science has the answer.

Originally Published: 
27 September 2022, Bavaria, Munich: Various heads of Lego figures are seen at a press event in the c...
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Kids love to put things in their mouths. Oral sampling is an innate behavior, so no parent of a baby or toddler or preschooler who hasn’t quite got the message is free from that fight. And if it’s food or the occasional couch cushion, it’s no big deal. Part of growing up. Of course, little metal and plastic things like spare change or, even more dangerous, coin battery buttons constitute a medical emergency and must be dealt with immediately. But what of Legos?

One of the more common culprits of improper ingestion, Lego pieces are tiny enough to go a lot of places they shouldn’t, leaving parents panicking and considering a trip to the E.R. Not so fast.

To help parents understand that not every foreign body ingestion is an emergency, a group of pediatricians took matters into their own hands — or, rather, mouths. Dr. Andy Tagg and his colleagues decided to swallow a Lego head and wait to see how long it took to reemerge, documenting and publishing their findings in the Journal of Paediatrics and Child Health.

“I had definitely swallowed a Lego as a child. I thought, well, there's no real data about how long it takes Lego to go through,” Tagg told Defector in their not-entirely accidentally hilarious step-by-step account of the experiment. “There's data about how long it takes coins to go through. It'd be really interesting to see how long it took to go through. I wondered if I could convince some of my friends to take it.”

After much back-and-forth discussion of the logistics of the experiment, including which head to swallow (“You want one that looks kind of shocked and scared as it goes down,” Tagg explained,), the six friends swallowed their Lego heads of choice and recorded their findings.

Before the doctors ingested the Lego heads, they kept a stool diary over several days noting the volume and consistency of their poops, and making a “score” for their bowel movements. The scientists then developed their own custom score which also doubles as one of the better dad jokes in science — the Stool Hardness and Transit (otherwise known as SHAT) score — to “standardise bowel habit between participants,” per the study. If a doctor had a high SHAT score, they were pooping more often and more loosely — if they had a low SHAT score, they were pooping less frequently, and likely had more firm poops. From this, they created the “SHAT score quotient” — the time it takes for the stool with the Lego head to pass through their bodies.

All the Lego pieces were retrieved in a timely manner, except one, but the team chalked that up to inadequate poop searching on the part of one of the experimenters. After it was determined that the unrecovered head likely passed but was missed due to a less thorough search method, the team concluded that a Lego head could travel the length of an adult GI tract in 1.7 days. That was known as the FART score (Found and Retrieved Time.) Each researcher had different results — some retrieved their Lego on the first day, and others did not until the third day.

Parents should remember, though, that a child’s GI tract is shorter than an adult’s, and everyone’s body works differently, so the time it takes small objects to pass might differ in children. Also, you should never leave a swallowed object up to fate. Call your pediatrician if the kid swallows, well, anything.

Ingestion of other small things, button batteries in particular, are even less benign and should be addressed by a medical professional as a serious emergency. That’s a reminder enough to keep a watchful eye on what your kids swallow, even if it turns out to be a benign object, rather than a dangerous one. And, even if you’re not super worried about the Lego head your kid swallowed, you should still make sure to reach out to your doctor if they do. You can even let them know about this study — so long as you was poetic about SHAT and FART scores.

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