Yes... unless you swallowed some poison and vomiting it up is the treatment that is called for. Vomiting brings up stomach acids that will rot your teeth faster than any soda can. That is pretty fast. Besides... Your intestinal tract was designed to go one way only.
It is bad to make yourself throw up, which is a condition known as Bulimia nervosa. This is because once food gets into the stomach, there are acids that mix with it before digestion. These acids are strong and if you throw up, the acids burn your esophagus, causing permanent damage to your throat. A lot of nutrients are also lost and this can cause malnutrition, dehydration and Vitamin and mineral deficiency among others. Check out http://www.livestrong.com/article/124738-bulimia-longterm-effects/.
Doing it once or twice.. only empties the stomach contents. Doing it regularly can cause malnutrition and severe damage to the esophagus due repeated stomach acid exposure. It can actually cause such severe damage as to cause a rupture in the esophagus.
it's too addicting, more than heroin, and it's completely confusing to you and everyone around you. plus you don't really taste the food... weird huh? don't start for all the reasons you're reading, it's sometimes too hard to stop.