Olive fruit extract is made from the fruit of the olive tree, Olea europaea, often using the water and pulp left over from pressing olive oil. Olives have been at the heart of Mediterranean food for thousands of years, and much of the interest in them comes from their polyphenols.
The best known is hydroxytyrosol, a polyphenol formed from oleuropein as olives ripen and are processed. Extra virgin olive oil naturally contains hydroxytyrosol and related compounds, and in the UK and EU there is an authorised health claim that olive oil polyphenols contribute to the protection of blood lipids from oxidative stress. That claim applies only to olive oil containing at least 5 mg of hydroxytyrosol and its derivatives per 20 g of oil, not to every olive extract.
On labels you will see olive fruit extract, Olea europaea fruit extract, or extracts standardised to hydroxytyrosol. Concentrated hydroxytyrosol is also authorised as a novel food for certain uses, which shows how closely these compounds are regulated.