A stomach rumble, also known as a bowel sound, peristaltic sound, abdominal sound, bubble gut or borborygmus (pronounced /ˌbɔːrbəˈrɪɡməs/; plural borborygmi), is a rumbling, growling or gurgling noise produced by movement of the contents of the gastrointestinal tract as they are propelled through the small intestine by a series of muscle contractions called peristalsis. A trained healthcare provider can listen to these intestinal noises with a stethoscope, but they may be audible enough to be heard with the naked ear as the fluid and gas move forward in the intestines (in the vicinity of, but not actually within the stomach). The lack of bowel sounds is indicative of ileus, intestinal obstruction, or some other serious pathology.

The scientific name borborygmus is related to the 16th-century French word borborygme, itself from Latin, ultimately from Ancient Greek βορβορυγμός (borborygmós). The Greek term is probably onomatopoetic in origin.

Other causes of stomach rumbles:

The word borborygmic has been used in literature to describe noisy plumbing. In Ada, Vladimir Nabokov wrote: "All the toilets and waterpipes in the house had been suddenly seized with borborygmic convulsions". In A Long Way Down (New York: Harper, 1959, p. 54), Elizabeth Fenwick wrote: "The room was very quiet, except for its borborygmic old radiator". Graham Greene's short story "Alas, Poor Maling" tells the tale of a luckless individual whose borborygmus takes the form of irritating noises that he has recently heard.

The word borborygmus has also been used in journalism to describe political turbulence. In an article in The Atlantic, Graeme Wood used the word to describe the effects of mass refugee migration into Europe: "Central Europe had to digest a massive refugee flow from Syria and Afghanistan, and the resulting borborygmus upended European politics and enabled a populist wave that has yet to crest."