Local irritation of the stomach, such as bacteria or food poisoning, activates the emetic center of the brain which in turn signals an imminent vomiting reflex. Retroperistalsis begins in the small intestine and pyloric sphincter.
Local stomach discomfort, such as bacterial infection or food poisoning, activates the emetic center of the brain which subsequently triggers an impending vomiting reflex. Retroperistalsis starts in the small intestine and pyloric sphincter.