According to this video, three out of every 10 people have to “go” every time they drink coffee. Are you one of those three? Then you need to watch. Here, the American Chemical Society delves into why coffee has a laxative effect. Contrary to popular belief, the effect is not caused by caffeine, but by coffee’s innate ability to stimulate production of two specific chemicals our bodies make naturally. These two chemicals stimulate movement in our large intestine, causing, well…you know the rest. What isn’t clear is what it is in coffee that causes the increase in production of these two chemicals. Attention all you future scientists: this is a pH.D. waiting to happen. Check out all the gross science below.