Causes of vomiting a yellow liquid include complications from surgeries such as gastrectomy and gastric bypass. Peptic ulcers block the pyloric valves preventing the stomach from emptying normally. Consequently, a person vomits a mixture of stomach acid and bile as a yellow liquid. Cholecystectomy, also causes vomiting of a yellow liquid, according to Mayo Clinic.
Yellow color in vomit indicates the presence of bile. The liver produces bile and gallbladder stores it. It is a greenish-yellow liquid that digests fats and eliminates worn-out red blood cells and toxins. Bile refluxes into the stomach when the pyloric valve fails to close. The weakening of the esophageal sphincter causes bile and stomach acid to reflux into the esophagus leading to yellow vomit. Stagnant food in the stomach causes gastric pressure that is relieved by dispelling a mixture of bile and stomach acid through vomiting, says Mayo Clinic.
Yellow vomit is acidic and damages the esophageal tissue. Vomiting a yellow liquid also causes heartburn. Consistently vomiting a yellow liquid causes Barrett's esophagus and esophageal cancer that is difficult to diagnose early. People without gallbladders suffer recurring bile reflux and often vomit a yellow liquid. Seek medical attention if weight loss and frequent, yellow-liquid vomit occur, as stated by Mayo Clinic.