In this article, contact allergy to, and the chemical composition of, tea tree oil (TTO) are reviewed. This essential oil is a popular remedy for many skin diseases, and may be used as neat oil or be present in cosmetics, topical pharmaceuticals and household products. Of all essential oils, TTO has caused most (published) allergic reactions since the first cases were reported in 1991. In routi...

Concentrated tea-tree oil has been classified as harmful according to the self-classification of the International Fragrance Association (IFRA) and is labelled with R-phrases R 22 (harmful if swallowed) R 38 (irritating to skin) and R 65 (may cause lung damage if swallowed) as well as the symbol Xn (harmful) (IFRA Labelling Manual 1, 2001). These indications of health hazards are also part of t...

Abstract Commercial tea tree oil (TTO) has to conform chemically the international standard ISO4730: 2017, which defines acceptable ranges for 15 main terpenoids therein. Lack of in‐house capacity technology typically required terpenoid quantification (GC‐FID) necessitates that Australian TTO producers outsource analyses commercial service providers. This is associated with high cost and slow t...

Polyphenols are a wide family of compounds found in fruits and vegetables, wine, tea, cocoa, and extra-virgin olive oil, which exhibit strong antioxidant activity by scavenging different families of Reactive Oxygen Species (ROS). One of the most effective members of the polyphenol family in terms of free radical scavenging is hydroxytyrosol, 2-(3,4dihydroxyphenyl)ethanol (Fernández-Bolaños et a...