Nausea is a symptom, rather than an illness or disease. The causes for it very often are not in the stomach itself, but somewhere else in the body. Nausea is often caused by a stomach virus. Nausea is usually harmless, in the short term. A good treatment for it can be not to take solid food (and to only drink non-alcoholic drinks, like water). Nausea can also occur during pregnancy, and is quite normal in that context.
- "Online Etymology Dictionary". etymonline.com. http://www.etymonline.com/index.php?search=nausea&searchmode=none. Retrieved 30 July 2010.