Overview of the canine digestive tract — mouth, esophagus, simple stomach, small and large intestine — and how dogs process a mixed, meat-leaning diet.
General educational reference only — not clinical or veterinary advice. Anatomy varies between individual animals; consult a licensed veterinarian for any health concern.
Mouth and esophagus
Digestion begins in the mouth, where teeth tear and break food into smaller pieces. Canine saliva moistens food and aids swallowing but contains little of the starch-splitting enzyme found in some other species. The esophagus is a muscular tube that moves the food bolus to the stomach by waves of contraction called peristalsis.
Stomach
The dog has a simple, single-chambered (monogastric) stomach that stores food and mixes it with acid and enzymes to form a semi-liquid called chyme. Gastric acid is relatively strong, which suits a diet that can include raw protein and bone. The stomach empties its contents gradually into the small intestine.
Small and large intestine
The small intestine — duodenum, jejunum, and ileum — is the main site of enzymatic digestion and nutrient absorption, supported by secretions from the pancreas and liver. The large intestine reabsorbs water and electrolytes and houses gut bacteria before forming feces. Relative to herbivores, the canine intestinal tract is short, reflecting an omnivorous diet that leans toward animal protein.
Liver and pancreas
The liver produces bile, stored in the gallbladder, which helps emulsify dietary fat. The pancreas releases digestive enzymes and bicarbonate into the small intestine and also regulates blood sugar through hormones such as insulin. Both organs are central accessory glands of digestion.
Sources
Veterinary anatomy and physiology texts; Merck Veterinary Manual (general reference)
