Ten to 25% of healthy persons experience bloating. It is particularly common in persons with the irritable bowel syndrome and constipation. While the cause of bloating remains unknown old explanations such as a excessive intestinal gas, exaggerated lumbar lordosis and psychiatric problems have been disproved. New suggestions include recent weight gain, weak or inappropriately relaxed abdominal muscles, an inappropriately contracted diaphragm and retained fluid in loops of distal small bowel. No treatment is of unequivocal benefit but a low FODMAPs diet, probiotics and the non-absorbable antibiotic rifaximin offer some hope. Treatment by weight loss, abdominal exercise, prokinetics and girdles need more study.