The digestive process begins in the stomach when the food enters it by exiting the esophagus. The function of the stomach is to chemically and mechanically separate the food into small pieces before it is ready to enter the small intestine. Stomach irritation can result in vomiting.  In dogs, their indiscriminate eating habit can result in foreign body ingestion leading to stomach irritation and vomiting.  One life-threatening condition that results due to stomach abnormality is gastric-dilatation-volvulus (GDV).