A gastrointestinal fistula occurs when an abnormal connection forms between part of the gastrointestinal tract and the skin or another organ, resulting in stomach acid leaking out.

Most GI fistulas (75-85%) occur as a complication of abdominal surgery. However, 15%-25% of fistulas evolve spontaneously and are usually the result of intra-abdominal inflammation or infection.

A gastrointestinal fistula (GIF) is an abnormal opening in your digestive tract that causes gastric fluids to seep through the lining of your stomach or intestines.

A fistula may be simple or complex. Simple fistulas form a short, direct track from bowel to skin. Complex fistulas drain to the skin through long, often multiple tracks via an abscess cavity.

An intestinal fistula is an abnormal anatomic connection between a part (or multiple parts) of the intestinal lumen and the lumen of another epithelialized structure or the skin.