Thousands of social media users have been horrified to learn what happens inside their bodies if they continually resist the urge to poop.
The gut-wrenching revelation came from online doctor, Karan Rajan, who responded to a viral video on the matter, in which a woman asks: "If you're absolutely bursting for a poo but decide to tough it out, eventually it just disappears... Like a missed call from an unknown number. So, where does it go?
"Does your body just quietly reschedule it for later? File it under 'pending'? Send it back to head office for further review."
Answering the woman's query, Dr Rajan told his 2.1 million followers they 'probably didn't want to know' what really goes on inside our intestines if we fail to release our faeces on time.
"When you repeatedly ignore the urge to poop, you're training your body to forget how to poop properly," he began. "The moment you ignore that urge, your body actually performs something known as 'reverse peristalsis'.
Water can be reabsorbed from poop if a person ignores their urge to push it out (Getty Stock Images) "The muscular contractions that normally push poop towards the exit reserve direction, and actually push it back up deeper into your colon."
The Instagram medic shared the analogy: "It's like your poop is reverse parking into a tighter spot."
He noted, however: "This isn't a metaphor, this is actual retrograde movement of faecal matter.
"The longer that stool sits in your colon, the more water gets reabsorbed into your body, so that nice, soft, ready-to-exit poop is now being rung out and desiccated into a brick."
Dr Rajan, who primarily works as an NHS surgeon, went on to note, however, that the 'real damage' doesn't happen within the colon, but in the brain.
"When stool enters your rectum, stretch receptors send a signal to your brain that it's time to unleash the chocolate kraken," he explained. "If you continuously ignore that signal, your receptors get desensitised.
Several poop-holders shared horror stories (Getty Stock Images) "The gun-brain connection weakens, and you're training your nervous system to stop telling you when it needs to go. Once that reflex is dulled, getting it back is hard work."
In agreement with Dr Rajan's assertions, one nutritionist replied in the comments: "Always, always tell my clients, family and kids never hold on to your [poop]. You must go when you get the urge! No matter where you are, even if it means a public toilet."
A concerned parent also begged: "Oh please tell this to every teacher who won't let kids go to the toilet when they need to!!"
A third user admitted they were previously guilty of this dangerous habit, claiming it severely damaged their health. They wrote: "I feel like this is exactly what I did as a very young child which in turn ended up with me having my large bowel aka colon removed as it no longer worked as it should.
"Please be aware of this, I was very lucky to not end up with an ileostomy."
Another worried viewer asked: "Ok I’ve neeeeever really allowed myself to poop in public, always wait till I get home…so, is this me?"