Nausea is a feeling that makes you feel an urgent urge to vomit. Nausea is also termed as "being sick to your stomach." Vomiting or throwing up forces the stomach's contents up through the esophagus and out of the mouth.   This also explains that it is a feeling of sickness or discomfort that may cause vomit at any time. The facts state that it is a side effect of some types of cancer...