Excessive production of stomach acid may result in the formation of peptic ulcers or trigger loose bowel movements, states Mayo Clinic. This condition is associated with Zollinger-Ellison syndrome, which is characterized by the initial development of gastrinomas.
The production of digestive acid in the stomach is regulated by a hormone called gastrin, which is secreted by the pancreas. The presence of gastrinomas (tumors found in the pancreas, the gland's surrounding the lymph nodes or in the duodenum) causes an unrestrained production of gastrin, explains Mayo Clinic. This condition in turn leads to an abnormal increase in stomach acid production. As of 2015, the definite cause of Zollinger-Ellison syndrome is still undetermined.