Betaine hydrochloride is an acidic form of betaine, a vitamin-like substance found in grains and other foods. Betaine hydrochloride is recommended by some doctors as a supplemental source of hydrochloric acid for people who have a deficiency of stomach acid production (hypochlorhydria). A deficiency of gastric acid secretion increases the likelihood and severity of certain bacterial and parasitic intestinal infections. A normal stomach’s level of gastric acid is sufficient to destroy bacteria. In one study, most fasting people who had normal acidity in the stomach had virtually no bad bacteria in the small intestine. Some bacterial colonization of the stomach occurred in people who had low levels of hydrochloric acid.