Thanks to the high production of hydrochloric acid, which is highly potent, the stomach regenerates its lining frequently. The stomach cavity has a powerful protective process in place that normally keeps the pH of the stomach balanced. Potassium ions help to modulate the hydrochloric acid, and the stomach lining itself produces high numbers of goblet mucous cells to protect the lining.

The pH of gastric acid is 1.5 to 3.5 in the human stomach lumen, the acidity being maintained by the proton pump H+/K+ ATPase. The parietal cell releases bicarbonate into the bloodstream in the process, which causes a temporary rise of pH in the blood, known as an alkaline tide. A pH of 7 is considered neutral. Below 7 pH is acidic and above 7 pH is basic. The farther away from a neutral ph of 7, the stronger the acid or base.