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Alginic Acid

Medically reviewed by Last updated on Mar 15, 2023.

Excipient (pharmacologically inactive substance)

What is it?

Alginic acid (C14H22O13) is a natural carbohydrate that comes from algae in seaweed (kelp) and is used in processed foods. It is also used in certain medications, such as Gaviscon liquid, to create a foam barrier for coating the stomach. Alginic acid is often combined with aluminum hydroxide and magnesium carbonate to form antacids.[1]

The combination of alginic acid, aluminum hydroxide, and magnesium carbonate is used to treat symptoms of stomach ulcers, gastroesophageal reflux disease (GERD), and other conditions caused by excess stomach acid. This medicine is also used to treat heartburn, upset stomach, sour stomach, or acid indigestion.[1]

Alginic acid does not appear to be absorbed or metabolized after ingestion.[2]

List of medications using Alginic Acid


  1. Alginic acid, aluminum hydroxide and magnesium carbonate. Accessed 8/21/2012.
  2. NCBI. PubChem. Alginic acid – compound summary. Accessed 8/21/2012.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.