CIR Safety Review: An extract of the leaves of Corylus avellana has been shown to have some anti-inflammatory activity. Additional data concerning extracts of the leaves and seeds of hazelnut trees were not identified.

While the CIR Expert Panel did not determine that the hazelnut leaf- and seed-derived ingredients presented any specific cause for concern, they concluded that there were not enough data available to permit a final conclusion.

Because some people are allergic to tree nuts, including hazelnuts, the Food and Drug Administration (FDA) Food Allergen Labeling and Consumer Protection Act requires that all food containing hazelnuts be clearly labeled.
Information about the FDA Food Allergen Labeling and Consumer Protection Act
http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformat...

More information about botanical ingredients.

The Hazelnut derived ingredients may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Directive of the European Union.
Link to the EU Cosmetics Directive: http://ec.europa.eu/consumers/sectors/cosmetics/documents/di...

In naming plants, botanists use a Latin name made up of the genus and species of the plant. For example, under this system the plant, the one species of hazelnut tree is known as Corylus rostrata Aiton. where "Aiton." stands for the name of the person who first described the type of plant specimen. Plants are also known by a common name that has been handed down through generations. For example, Corylus rostrata is also called the beaked filbert. These common names may vary from country to country. Therefore, Latin names, which are more likely to be recognized in many countries, are frequently used on the label of a product to identify an ingredient made from plants.