The "rumble" or "growl" sometimes heard from the stomach is a normal part of digestion. It originates in the stomach or upper part of the small intestine as muscles contract to "clean house" — moving food and digestive juices down the digestive tract.
Although this muscle contraction happens whether or not food is present, rumbles are more common after the organism has gone several hours without eating. This may be why many people associate a "growling" stomach with hunger.
Rumbles may also occur when there is incomplete digestion of food that can lead to excess gas in the intestine. This can be due to incomplete digestion of carbohydrate-containing foods including milk or milk products (lactose intolerance), fruits, vegetables, beans, legumes and high-fiber grains. Rarely, excessive abdominal noise may be a sign of digestive disease, especially when accompanied by bloating, pain, diarrhea or constipation.
Some people find rumbling embarrassing. Some opt to eat small snacks periodically to be sure their stomach is never completely empty. If you choose to do this, be forewarned the extra calories may contribute to unwanted weight gain. However, there is no foolproof way to keep your stomach quiet.