This research focuses on the in vitro evaluation of commercially available marketed antacid preparation (tablet) in Bangladesh. This research work deals with chewable non - systemic antacid preparations which are usually used in combination. We have done our experimental work by measuring the acid - neutralizing capacity in two ways. These are simple complexometric titration method and pH measurement method. Then we compare those results. Then we have done assay of those antacid preparations. And we also work various tests for evaluation of tablet. These are weight variation test, thickness...