Nausea and vomiting
Nausea and vomiting are symptoms of an underlying illness and due to a not a specific disease. Nausea is the sensation that the stomach wants to empty itself, while vomiting (emesis) or throwing up, is the act of forcible emptying of the stomach. The term "dry heaves" (retching) refers to an episode of vomiting where there is no food in the stomach to vomit, and only small amounts of clear secretions are vomited.
Vomiting is a violent act in which the stomach, the esophagus, stomach, and small intestine forcibly expel contents of the stomach (and sometimes the small intestine) in a coordinated fashion.