A preliminary in vitro acid neutralizing capacity test of twelve traditional Ayurvedic antacidswere performed in this study. Five traditional preparations of ash of conch shell, ash of oyster, ash ofpearl, limestone, and ash of cowrie showed high acid neutralizing capacity similar to standard antacidcombination of Al(OH)3 and Mg(OH)2. Among these the ash of conch shell found the highest acidneutralizing capacity. The ash of tamarind and ash of Achyranthus aspera showed moderate acidneutralizing capacity. The acid neutralizing capacity of red ochre; ash of iron; mixture of niter, alum andammonium chloride; saltpeter; and ash of mica found below the USP 23 limit.