GERD acidity

Natrum Phos 6x, 3 tablets after each meals will reduce the acidity. To heal the system, give Arnica 30c, in wet dose, twice a day (Joepathy)

PHOSPHORUS 200 and ANTIMONIUM CRUD 200 "together"
Corrosive Acidity: take ARGENTUM NITRICUM 30c & KALI BICHROMATUM 30c Two doses of EACH alternately with a gap of about 4 hours in a day, for 10 days.
Half a cup of chilled milk without sugar morning & evening to be taken in small sips will help you to get some more comfort. (Daktersaab in abcforum)