vomiting

the REFLEX ACTION wherein the stomach contents are expelled through the mouth because of the contraction of the DIAPHRAGM and abdominal wall muscles. Vomiting is caused by stimulus of the appropriate centre in the BRAIN , but the primary agent is usually a sensation from the stomach itself, e.g. a gastric disease or some irritant. Other causes may be the action of drugs, some effect on the inner EAR (e.g. MOTION SICKNESS ), MIGRAINES , etc.