請問這種藥GAVISCON ADVANCE可以醫什麼病

制酸劑（Antacid）

一種常用的抗酸質藥物，作用是使酸鹼度（PH）提高以減低胃酸的刺激及傷害
胃酸分泌過多所引起的不適；消化性潰瘍、胃炎、消化性食道炎及裂孔疝氣所引起

的酸度過高症狀。
there are too less side effect

that is for indigesting and heartburn.
it is stronger than the gaviscon original. there's another one called the gaviscon double action as well.

(extra strength) it contains double the concentration of sodium alginate compared to the gaviscon original.

can be taken during pregnancy.

as it contains sodium, you should consult your doctor if you have been advised to follow a low sodium (salt) diet before taking any products by gaviscon.
do not take if you know you are allergic to any of the ingredients. (please check the label on the packet)

you may feel bloated if you have taken too much. it is unlikely to cause any harm but DO consult your doctor or pharmacist.
do not use after expiry date, which should be printed on the label.

for more information please see the website below:
http://www.gaviscon.co.uk/understanding_heartburn_and_indigestion/causes_symptoms.php

this is the official website from UK (it's a UK product)