Regurgitation is the act of bringing up food or liquid from the stomach that has been partially digested. It is often accompanied by NAUSEA, HEAVING, VOMITING, and RETCHING. NAUSEA is an unpleasant feeling in the stomach that can lead to VOMITING. HEAVING is a strong, involuntary contraction of the chest muscles that can cause VOMITING. VOMITING is the forceful expulsion of the contents of the stomach through the mouth. RETCHING is a reflexive spasm of the stomach muscles that can lead to VOMITING.