alkaliser vs gastric antacid

alkaliser and gastric antacid both are nouns.

Word	Noun	Adjective	Verb	Adverb
alkaliser	Yes	No	No	No
gastric antacid	Yes	No	No	No

As nouns, alkaliser and gastric antacid are synonyms defined as:

alkaliser and gastric antacid: an agent that counteracts or neutralizes acidity (especially in the stomach)

Other synonyms of alkaliser include alkalizer, antacid, antiacid.

alkaliser (noun)	gastric antacid (noun)
an agent that counteracts or neutralizes acidity (especially in the stomach)	an agent that counteracts or neutralizes acidity (especially in the stomach)