While it may sound unpleasant and odd, it is feasible to vomit your own feces. Throwing up excrement, often known as "feculent vomiting" in medical literature, is generally caused by an obstruction in the intestines. 11 percent of people who vomit do so with no apparent cause. The remaining 89 percent have a reason: food poisoning, acid reflux disease, esophagegy, cirrhosis, cancer, and more. People can survive throwing up their meals or snacks. In fact, this is usually what saves lives for people who are starving or otherwise deprived of adequate nutrition. The problem arises when these vomits contain elements other than liquid. This can occur if you have eaten solid foods without clearing your stomach first (such as eating a meal straight from the refrigerator), if you have taken drugs that affect the movement of material through your digestive system, or if you have ingested a large amount of material that cannot be absorbed into your bloodstream through your gastrointestinal tract. In such cases, digestion ceases at its most important stage: absorption. Any undigested food remains in your stomach and intestines where bacteria begin to break them down further. If this process continues long enough, bacteria in your gut will eventually produce carbon dioxide and water vapor through their metabolic processes. The resulting gas builds up behind the point of obstruction in your intestine and forces its way out through your mouth or nose.