(Pronounced bor-buh-rig-mus) is the name for the rumbling sounds made by the stomach. These are caused by the movement of fluids and gases, as food, acids and digestive juices migrate from the stomach into the upper part of the small intestine. The average body makes two gallons of digestive juices a day. The hydrochloric acid in your stomach is so strong it could eat into metal, but a special form of mucus protects your inner linings from this acid along the length of its journey.