Digestion is the main cause of abdominal sounds or gurgling noises in the stomach, according to Healthline. These noises come from the small and large intestines, and they normally occur when the intestines process food.
The stomach typically makes abdominal sounds a few hours after a person eats or when he is sleeping at night, notes Healthline. Hunger also causes the stomach to grumble because certain substances in the brain trigger the desire to eat and cause the delivery of signals to the stomach and intestines. Upon receiving the signals, the digestive system's muscles start contracting and making noises.
Hypoactive abdominal sounds refer to reduced noises when the intestinal activity starts slowing down, whereas hyperactive bowel sounds are very audible noises that other people can hear, explains Healthline. These bowel sounds are normal; however, frequent occurrences of either type of noises may be a symptom of an underlying medical problem.
Abdominal sounds possibly indicate an illness if other symptoms, such as constipation, frequent diarrhea, vomiting, nausea and excess gas, accompany them, states Healthline. Unexpected weight loss, bloody stools, and heartburn that does not resolve with over-the-counter medications are other accompanying symptoms of stomach noises. Anyone who experiences these symptoms along with abdominal sounds or abdominal pain should consult a doctor, as they can be associated with an infection, trauma, blood clot or hernia.