DORA: So what is vomit, anyway?
WENDELL: Vomit's really interesting. Ever wonder about it, Dora?
DORA: Don't make me puke, Wendell.
WENDELL: Come on, Dora. Like, what is it? why do you do it? And why is it that very special color?
DORA: Okay, Wendell, so what is it?
WENDELL: Well, vomit's the mushed-up, half-digested food from your stomach along with a little slimey stomach mucus, a dash of saliva, and some acids and other chemicals that help digest food.
DORA: Yuck. So glad I asked!

DORA: But why do we do it?
WENDELL: You know, your digestive system is one long muscular tube. Your muscles are extremely strong and they usually squeeze the digesting food down the tube -- not up!
DORA: So what happens if (document.images)I'm hanging upside down from parallel bars? Do I throw up, then?
WENDELL:Nope. Your muscles still move the food down the tube most of the time.
DORA: Cool! But then why do we sometime throw up?
WENDELL: Sometimes you eat something that doesn't agree with you in a big way. Or you eat spoiled food or food that contains germs. Or you eat too much. Or the twists and turns on a roller coaster are too much for you. Or you feel way too nervous.
DORA: Wendell, this is making me feel a little queasy.

DORA: But how do we vomit?
WENDELL: Ah! Why vomiting is a beautiful symphony of coordinated activity. The muscles in your abdomen contract and squeeze down on our stomach, then the valve between your stomach and the tube that leads from your mouth to your stomach opens, and the contents begin to rise up. The pressure forces open the valve in your throat -- and there she blows! Puke-o-la!
DORA: Now that's gross, Wendell!

DORA: Why is vomit puky green and yucky tasting?
WENDELL: That lovely color green is from a chemical called bile. It doesn't come from your stomach but from further down in your digestive system. Sometimes, some of the mush way down in your intestines gets squeezed back up into the stomach and then keeps going up,up,up!
DORA: Great....But what does the bile do?
WENDELL: Good question. It helps break down fats and starches you've eaten so they can be used by your body.
DORA: And that yucky taste in your mouth. Where does that come from?
WENDELL: You're tasting a lovely mix of stomach acid and half digested food. But Dora, don't worry! You hardly ever throw up, right? Given how much you humans eat every day, I wouldn't complain. Your body is doing a pretty stupendous job of digesting!