Role of hydrogen and methane breath testing in gastrointestinal diseases

The hydrogen and methane breath test represents a very simple, cheap, non-invasive diagnostic procedure to evaluate intraluminal events occurring in the gastrointestinal tract. Its clinical applications are, first of all, lactose malabsorption and small bowel bacterial overgrowth, but it has also been used to evaluate mouth-to-cecum transit time, sweetener malabsorption and intestinal mucosa integrity. Methodological aspects should be better evaluated and an improvement of its accuracy should be obtained through the adoption of new protocols.