The water-like red substance that sometimes occurs in a ketchup bottle when you haven't shaken it before pouring it on your plate.
Oh no, I poured ketchup diarrhea all over my freedom fries! Darnit, I should have shaken the bottle.
by Treklemmer April 26, 2010
When you tip a ketchup bottle and it just instantly pours out, That's ketchup diarrhea.
Ketchup diarrhea can be messy.
by Pitchy June 25, 2015