Bismuth subsalicylate is scientifically validated for use in treating dyspepsia, though the strength of the evidence is moderate. Dyspepsia, or indigestion, encompasses a group of symptoms including discomfort or pain in the upper abdomen, bloating, and nausea. The compound is the active ingredient in over-the-counter medications such as Pepto-Bismol, which are widely used for gastrointestinal complaints.

The mechanism by which bismuth subsalicylate provides relief from dyspepsia is multifactorial. It has mild antacid properties, allows for the absorption of excess stomach acid, and may stimulate protective mucus production. Additionally, its salicylate component has anti-inflammatory effects on the gastric mucosa. Bismuth subsalicylate also possesses mild antimicrobial activity, which may benefit patients with dyspepsia related to Helicobacter pylori infection, though it is not used as monotherapy for this purpose.

Clinical evidence supporting its use in dyspepsia comes from randomized controlled trials showing modest improvement in symptoms compared to placebo. For example, a 1990s randomized, double-blind study found that bismuth subsalicylate improved symptoms in patients with non-ulcer dyspepsia. However, most of the clinical evidence is moderate in quality, with relatively small sample sizes and some methodological limitations. Guidelines from gastroenterological societies often mention bismuth subsalicylate as an option for symptomatic relief, but not as a first-line or definitive therapy.