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Acetic Acid

Medically reviewed by Last updated on May 18, 2023.

Excipient (pharmacologically inactive substance)

What is it?

Acetic acid (C2H4O2) is a widely used industrial chemical reagent and solvent often used in industrial processing. It exists as an acidic liquid or crystals. Vinegar contains roughly 5-15 percent acetic acid. Acetic acid is approved for use in the U.S. as a food additive, and is used mainly to adjust pH and as a pickling agent for vegetables.

Pharmaceutically, glacial (or water-free) acetic acid is used as a hypotonic urologic irrigation for the urinary bladder. It exerts an antimicrobial action and lowers the pH against a variety of bacteria (especially ammonia-forming bacteria) that may gain access to the urinary bladder in patients who require indwelling urethral catheterization.[1]

Acetasol and Vosol are over-the-counter eardrops that contain acetic acid and are used to treat outer ear bacterial or fungal infections (otitis externa). They are not effective for inner ear infections (otits media).[2]

List of medications using Acetic Acid


  1. DailyMed. Acetic Acid irrigant. B. Braun Medical Inc. Accessed 8/21/2012.
  2. Acetasol HC Solution. Accessed 8/21/2012.

Further information

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