Described is an anti-acid pharmaceutical composition, and a process for making it, for rapid and long lasting neutralization of gastric acidity with a mucosa-protecting activity in powder form to prepare, by dispersion in water, a pharmaceutical solution or suspension for oral use wherein the composition comprises: - sodium alginate. - a soluble anti-acid agent or a combination of anti-acids. - an inhibitor of proton pump - diluent and sweetening agents. wherein: (a) at least 30% of sodium alginate present in the formulation along with the total of the proton pump inhibitor are homogeneously distributed over the surface of the total anti-acid agent or the combination of anti-acids of the composition； and (b) the rest, about 70%, of sodium alginate present in the formulation contains a percentage of humidity of less than 2%.
