Throwing up stomach acid is commonly caused by acid reflux or gastroesophageal reflux disease (GERD). This happens when the lower esophageal sphincter (LES), a muscle that normally keeps stomach contents from coming back up, doesn't close properly. As a result, stomach acid can flow back into the esophagus and throat, irritating them and sometimes causing nausea and vomiting. Factors like eating fatty, spicy, or acidic foods, drinking caffeine or alcohol, and certain lifestyle habits can worsen this condition. Vomiting stomach acid is often accompanied by symptoms such as heartburn, a sour taste in the mouth, and indigestion. If this happens frequently or severely, it may need medical evaluation and treatment to avoid complications like esophagitis or ulcers.
Other causes of vomiting stomach acid can include bile reflux and intestinal blockages, but acid reflux and GERD are the most common reasons for the symptom described.
