Rosemary is an evergreen shrub with the Latin name Rosmarinus officinalis L. Plants with the surname officinalis are typically old medicinal plants.
An extract of the plant leaves has been used commercially for many years as an approved antimicrobial agent in a range of foods, dietary supplements, cosmetics and personal care products. The extract contains a dozen different plant compounds that act as antioxidants, the main effect of which comes from substances such as carnosol, carnosic acid and triterpenes.
Rosemary extract has E number 392 and is considered by the European Food Safety Authority (EFSA) to be a very safe substance. For example, EFSA accepts up to 400 mg/litre or kilogram in food supplements in tablet, capsule or liquid form.