The organs that work together to convert food into nutrients and energy are known collectively as the digestive system. When you eat, your food travels along alimentary canal, or gastrointestinal tract. This alimentary canal starts with the oral cavity, continues through the pharynx, esophagus, stomach and the small and large intestines, and ends with the rectum.

Digestive allergy symptoms include daily pain in the stomach or abdomen; extreme distension; constipation; difficulty swallowing; vomiting and feeling nauseous; heartburn; diarrhea; dehydration; and even malnutrition.