Antacid

<p>Antacids either directly neutralize acidity, increasing the <a href="http://en.wikipedia.org/wiki/PH" title="PH">pH</a>, or reversibly reduce or block the secretion of acid by gastric cells to reduce acidity in the stomach. When gastric <a href="http://en.wikipedia.org/wiki/Hydrochloric_acid" title="Hydrochloric acid">hydrochloric acid</a> reaches the <a href="http://en.wikipedia.org/wiki/Nerves" title="Nerves" class="mw-redirect">nerves</a> in the gastrointestinal <a href="http://en.wikipedia.org/wiki/Mucosa" title="Mucosa" class="mw-redirect">mucosa</a>, they <a href="http://en.wikipedia.org/wiki/Nociception" title="Nociception">signal pain</a> to the central nervous system. This happens when these nerves are exposed.</p>