Carnosic acid is a natural benzenediol abietane diterpene found in rosemary (Rosmarinus officinalis) and common sage (Salvia officinalis).

[1] Dried leaves of rosemary and sage contain 1.5 to 2.5% carnosic acid.

Carnosic acid and carnosol, a derivative of the acid, are used as antioxidant preservatives in food and nonfood products, where they're labelled as "extracts of rosemary" (E392).

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