Why is sodium hydroxide NOT suitable for curing an upset stomach

List three oxides that will react with hydrochloric acid

Normally an upset stomach is caused by an increase in stomach acidity, i.e. your molarity of HCl is increased

NaOH + HCl --> NaCl + H2O

NaCl is table salt and H2O is water, Sodium is bad for you in large amounts taken over extended periods, but your body can cope with a sharp excess quite readily.

You need to consider whether this reaction is endo or exothermic? How endo/exothermic is it? Would this make it unsuitable for curing upset stomach?