A neutralization reaction is a specific type of acid-base reaction in which the reactants are an acid and a base (but not water), and the products are often salt and water.

Acid + base ⟶ salt + water

To illustrate a neutralization reaction, consider what happens when a typical antacid such as milk of magnesia (an aqueous suspension of solid Mg(OH)₂) ingested to ease symptoms associated with excess stomach acid (HCl):

Mg(OH)_2(s) + 2HCl_(aq) ⟶ MgCl_2(aq) + 2H₂O_(l).

Note that in addition to water, this reaction produces a salt, magnesium chloride.