WARNING: Graphic image at the end of this article
They say you shouldn't run with scissors but maybe they should be advising people not to run with toothbrushes either.
Reddit user "StickyMustache" shared his painful lesson of why you should never run with a toothbrush in your mouth.
It doesn't matter how good you think you are at multitasking, brushing your teeth should never be combined with any other activity.
In the "Today I F****d up" subreddit, the user posted the story (and the awfully graphic picture) of what happened when he had to run to his car while brushing his teeth.
"I woke up this morning and started brushing my teeth just like any other morning," he wrote.
"I realised I was running a bit late and that it was dumping snow (I live in Northern Idaho), so I ran outside to start my car with my toothbrush still in my mouth."
(You can already tell this is going to end in disaster, right?)
"It was freezing outside and I was not properly dressed so I ran back to my house. Right when I was approaching, I stumbled slightly on the bottom stair and hit the toothbrush on my door, jamming it into the back of my mouth."
"It hurt a little bit but I didn't think anything of it and continued brushing my teeth. When I went to spit and rinse, there was more blood than toothpaste. I opened up, said 'ahhhhh,' and looked in my mouth to find that the toothbrush had poked a hold in the back of my throat. Stitches in the back of your throat are not pleasant."
The Reddit user shared a link to a photo of the inside of his mouth after the incident.
The image has been seen more than 93,000 times in less than 20 hours.
It's not pretty.
Scroll down at your own risk.