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. 2026 Mar 24;44(3):235–248. doi: 10.1159/000551414

Fig. 2.

On the left, the mechanism of action of raft-forming alginates is represented. The acid pocket is presented as a layer of red and orange balls of pH 1–3 sitting on top of an ingested meal in the stomach. On contact with this acid, the alginate has precipitated to form a buoyant raft, presented as a white layer, within which neutralized acid is represented by yellow and green balls of pH 4–6. A white layer on the sides of the esophagus shows how alginate has refluxed in lieu of stomach acid, adhering to and protecting the esophageal mucosa. On the right, the mechanism of antacids and acid suppressants are represented. The neutralization of refluxed acid in the esophagus by antacids is represented by red/orange balls turning green. The magnified parietal cell shows how proton pump inhibitors and histamine-2 receptor antagonists block acid secretion; proton pump inhibitors by inhibiting the proton pump and histamine-2 receptor antagonists by competing with histamine for binding at the histamine receptor.

Mechanism of action of the major types of nonprescription treatments available for self-management of reflux-like symptoms. H2RA, histamine-2 receptor antagonist; H+K+ATPase, hydrogen potassium ATPase; PPI, proton pump inhibitor *Raft-forming alginate products only. Alginate formulations differ in their acid-neutralizing capacity and raft-forming capabilities.