How do antacids reduce indigestion?

My experience as a child and in dealing with my children, tummy ache
is something I've never liked to face.

When it comes to indigestion this information I came across has proven
to be quite enlightening. Last week I had my kids facing indigestion
challenges and that prompted me to research the role of Antacids.

Common symptoms of indigestion are

Upper Abdominal pain or discomfort

Bloating (tummy feels uncomfortably full)

Excessive gas

Nausea and Vomiting

Burning feeling in upper abdomen/heart burn

"Gastric juice, the digestive juice used by our stomachs to digest
food, is quite acidic -acidic enough in fact, to digest zinc metal!
Our stomachs have a special lining that normally can handle these
conditions by constantly shedding its cells and replacing them.

Occasionally, however, such as when we eat something that is difficult
to digest (like pizza with everything on it) or when we are under a
lot of stress, our stomachs produce more acid than they can handle.
The excess acid causes the stomach to shed the cells of its protective
lining faster than it can replace them.  If this happens occasionally
we feel the discomfort of indigestion.  If it happens a lot we can
wind up with an ulcer.

To take care of the excess acid, we can take an antacid.  Antacids
contain weak bases.  Bases neutralize acids by reacting with them to
form water and a salt.  The reason weak bases are used instead of
strong bases is because strong bases would neutralize too much acid
and would most likely kill you."

(Lansing State Journal, October 26, 1994)
http://www.pa.msu.edu/sciencet/ask_st/102694.html