Blue or green, because antacid is basic.
Dark Vilolet
That really depends on the strength of the acid, the antacid, and how much of each are present in a mixture. Phenolphthalein is a pink in the presence of higher strength bases (pH > 8.2), orange...
green or pink or maybe yellow or MAYBE EVEN BLACK OR OR OR MAYBIEE EVEN A GOLD "HALLAJUIEA HALLALUIA .............."
yes and so is red and blue :P but in science the colors are red blue and green