Indigestion remedy (7)
I believe the answer is:
antacid
'indigestion remedy' is the definition.
(medicine for indigestion)
This is all the clue.
(Other definitions for antacid that I've seen before include "Substance used to treat stomach upsert" , "Stomach drug" , "remedy for tummy trouble?" , "Medicine to settle the stomach" , "Indigestion relief" .)