If you have little kids you know that they are always putting objects in their mouths and it only takes a second before they swallow something. The most common ages for swallowing objects are 6 months to 3 years, when everything goes into the mouth. Parents panic and frantically call the pediatrician to see what they can do. Most of the time, the answer is "Just wait". The child will poop it out naturally. (The exception to this is if it is a battery or magnet, which can be dangerous to the intestines. That deserves a visit to the ER)
A group of enterprising pediatricians who deal with the calls from the parents of object eating kids designed a cool experiment that was published in The Journal of Pediatrics and Child Health. These brave doctors swallowed small legos and tracked how long it would take for it to pass through their GI system.
They even came up with their own study nomenclature: “Pre‐ingestion bowel habit was standardised by the Stool Hardness and Transit (SHAT) score,” the study read. “Participants ingested a Lego head, and the time taken for the object to be found in the participants stool was recorded. The primary outcome was the Found and Retrieved Time (FART) score.
We now know, thanks to their bravery, that the average time to pass an object is really quite short. They found it in the stool 1.71 days after swallowing. No complications were noted during the study, suggesting that the tiny plastic toy had little to no affect on the digestive tract of the participants.
Of note, is that one male pediatrician never did find the toy. The poop search may have been deficient in his case and we can only presume that it was flushed down the toilet (Kind of like Nemo).