Although it varies considerably from person to person, bowel sounds occur every two to five seconds. These sounds occur as food and liquids move through the intestines.
Because of the variability among individuals, medical personnel usually do not listen to bowel sounds during physical examinations unless there are symptoms of abdominal problems. When the procedure is required, typically a stethoscope is placed on each of the four regions of the abdomen for several seconds. Sometimes variations from the expected norm are discovered. For instance, with certain inflammations, including peritonitis, no sounds are heard. In other inflammations, such as those that cause diarrhea, the sounds are almost constant. Abdominal obstructions lead to very frequent sounds, or rushes, that decrease and then stop.