Stomach noise — such as rumbling, gurgling and growling — typically is due to normal digestion. Stomach growling can occur when you're hungry. But it can also occur after eating or between meals when food is being digested.
Hunger and appetite are controlled by a complex system of nerve signals and hormone-like substances primarily made by your digestive system. When you haven't eaten for a while, these substances are released and cause a part of your brain called the hypothalamus to "switch on" your desire to eat. A message is then sent to your stomach and intestines. This triggers muscle contractions and the release of acids and other digestive fluids — which causes the rumbling, grumbling sounds you hear — as your body prepares for you to eat. The thought, sight or smell of food also can trigger this response.
Sometimes excessive stomach noise can be a symptom of an underlying gastrointestinal disorder, such as irritable bowel syndrome. But in such cases, stomach noise usually is accompanied by other signs and symptoms such as bloating, cramping, diarrhea or excess gas.