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A Short List of ‘Fun Facts’ Dr. Karl Has Taught Me Against My Will

Until 2022, I had never heard of a “Dr. Karl”. Nor had I considered the concept of “poo particles”, or contemplated the existence of “cubical poo”.
Doctor Karl lookin
Patrick Riviere / Getty Images

When Doctor Karl first popped up on my TikTok feed, I had already lived 26 gorgeous and fulfilling years characterised by what I now know to be unmitigated, unadulterated, and blissful peace. 

In fact, until 2022, I had never even heard of a “Dr. Karl”. I had never spent more than a fleeting nanosecond considering the concept of “poo particles”, nor had I ever contemplated the existence of “cubical poo”. I had certainly never, ever, asked the question, “Can you taste things with your balls?”.


But that’s all different now. I am different now. What I now know cannot be unknown. 

Doctor Karl, or, Karl Sven Woytek Sas Konkovitch Matthew Kruszelnicki AM, is an Australian popular science personality. He’s been a stalwart of the ABC across radio and television for a while now, but since joining TikTok he’s reached a whole new generation, and a whole new level of popularity. The 74-year-old was born in Sweden and grew up in an Australian refugee camp. As he explained on his TikTok page, his career includes degrees in “physics and mathematics, biomedical engineering, and medicine and surgery”.

After assessing Dr. Karl’s Wikipedia page, it became clear to me that he is a baller. A very cool guy. A national treasure, if you will. In his first job, he worked as a physicist for the Wollongong Steel Works, where he tested the steel that was to be for Melbourne’s Westgate Bridge. He quit when his boss wanted him to fake his results. Baller. 

He was a childrens’ doctor for a time, before leaving the profession after witnessing the first child to die from whooping cough in 20 years. He said the death was purely a result of a television show trying to raise controversy around the whooping cough vaccine, causing a drop in vaccines and thereby a drop in herd immunity. 

"That very strongly influenced me to go into the media,” Dr. Karl said in a radio interview. “Because I felt like I could do more good there (convincing people to vaccinate). And as a result, I gave up the best job of my life, which was being a doctor in a kids' hospital, so I could do more good in the community." National treasure.


He was also really hot in the 60s and 70s, as evidenced in the video below.

But now in his quest to illuminate the TikTok community to the many joys of science, Dr. Karl has taught me some terrible, terrible things. And it has all been against my will. Here’s just a few.

1. Poo particles

A disarmingly chipper Dr. Karl asks one very simple question: “Do you flush the toilet with the lid up?” 

Sometimes… hmmm maybe oftentimes, the viewer may think to themselves.

“When you flush the toilet with the lid up, a POLLUTED plume of bacteria and water vapour just ERUPTS out of the flushing toilet bowl,” he damn near shouts.

Dr. Karl goes on to say the poo particles will float around your bathroom for a few hours before they all eventually land.

“They WILL land,” Karl assures the aghast viewer. 

“And some of it COULD LAND on your TOOTHBRUSH,” he pauses, presumably so the viewer has time to projectile vomit. 

“So you COULD BE brushing your teeth with TOILET WATER.”

Dr. Karl please!!!!!!!!!! 

But, more importantly, why the FUCK do bathrooms contain toilets? Not mine, thankfully, however there is a bunch of art decorating the walls in my loo closet that I now know can NEVER leave those four walls.

2. Fart particles

Oh. This one is good. And by “good” I mean likely to leave a permanent scar on your psyche

Dr. Karl kicks off with some positive affirmation: Everybody farts. In the volume between half and one-and-a-half litres a day (why farts are measured in litres is a question that will haunt me for perpetuity). They happen because bacteria in your large intestine “go to town” eating what your little intestine can’t digest, generating the byproduct of “fart gas”.


When you hold in your farts, Dr. Karl deadpans, the fart gases go into the blood vessels in the large intestine and “overwhelmingly” go out through your lungs. 

“AKA you breathe them out!”


I understand this message may be liberating for some – when Shrek said “better out than in”, he was not fucking about. 

However, as I sit here, thinking of all the times I’ve held it “in”, I do wish I was dead.

3. Shower farts

Dr. Karl is the kind of guy who will sit there in the sunlight, on a comfy outdoor chair, wearing Kris Jenner sunglasses over his regular glasses and a chaotic shirt with strawberries printed all over it, and calmly explain the scientific circumstances precluding the most disgusting human experiences, blow-by-blow.

Why do shower farts smell so bad? There are no less than five (FIVE) reasons, he explains. The first is that your fucking clothes usually act as a “filter” for all of the “juices”... (when will the torment end…) And of course, in the shower, you don’t have those on to save you.

The second is that shower cubicles are a lot smaller than regular rooms, so you’re trapped in there with the “stinky molecules”, making them even more likely to end up in your nose.

Reason three is that the falling water in the shower creates “wind currents” which combine with the rising heat of the shower to create a fucking vortex that shoots those fart particles up to your nose.


Fourth, shower water is hotter than your skin and the air so all these chemical reactions are taking place faster.

Finally, the high humidity interacts with your olfactory system by INCREASING the sensation of receiving smells, ensuring everything smells more intense. 

The question is, given what you now know about holding in your farts, IS IT WORTH IT???

4. Pee hydration (?)

Okay, so, I SPECIFICALLY remember a Dr. Karl video about dehydration. The video included the galling information that when you are dehydrated, something in your system starts taking the water from your bladder, or whatever. The disgusting through-line was that your body starts using pee water to rehydrate. Now, I have combed the internet and Dr. Karl’s page for this video, but it is nowhere to be found. All that my search has yielded is information as to whether you should drink your pee if lost on a desert island (maybe). Perhaps he deleted the video because it was incorrect (I hope, as I ruminate on the woeful 200 mls of water I’ve consumed in 24 hours). My sister also remembers this video, so I’m not imagining it, but it could be some sort of Mandela Effect situation where it wasn’t even a Dr. Karl video that brought us such information. Given his propensity to cheerfully deliver the most disturbing yet useful fun facts about the bodily functions we’d rather not think about, can you blame me for being absolutely almost-certain it was him?


Anyway, that’s all for now. 

Dr. Karl is still making videos, so we’re not safe from further damaging information yet. 

I hope you’ve learned something, and I hope it was against your will. 

Don’t hold in your farts! Drink water! Flush with the fucking toilet lid DOWN. 

Send this to a friend and ruin their day! 

At a party with a bunch of strangers and feel the need to make the room go silent in seconds? Share this information! They’ll love it.

Dr. Karl, what would we do without you? (Live lives filled with blissful peace, probably).

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