Many people are quick to blame caffeine for the laxative effect coffee has. However, if this were true, then why don’t energy drinks or soda have the same effect? And why does decaf coffee have the same effect as caffeinated coffee? A video from the American Chemical Society’s Reactions series answers the question that everyone wants to know, but very few want to ask.

“Some of you folks out there know firsthand that a cup of coffee almost immediately means a trip to the bathroom,” the video description reads. “But what's inside a cup of coffee that makes you have to go #2? Today on Reactions, we bring you the answer — to the best of our scientific knowledge.”

First, if coffee does make you poop, then you’re one of the lucky few (or unlucky, depending on how you look at it) who experience this effect from drinking a cup of joe. Between 30 and 40 percent of the U.S. population says drinking coffee makes them poop. Frequent coffee drinkers who don’t feel the need to poop after drinking a cup have likely built up a tolerance.

Scientists know that coffee’s acidity helps with stimulating the distal colon which, in turn, leads to waste being rapidly dispelled from the body. What exactly triggers this effect gets a little more complicated. There are around 1,000 compounds found in coffee, any of which can cause our body to break down protein more efficiently, our stomach to dump its contents quickly into the large intestine, or increase our body’s level of cholecystokinin and gastrin — two hormones that help with food digestion.

Watch the video to learn more.