Safety assessment and adverse drug reaction reporting of tea tree oil (Melaleuca aetheroleum)

Abstract

Tea tree (Melaleuca alternifolia) essential oil is widely used as an antiseptic. It mainly consists of monoterpenes with terpinen‐4‐ol as the major constituent. The aim of this study was to review literature on safety data about tea tree oil and to assess its safety by investigating 159 cases of adverse reactions possibly caused by the oil, reported to the World Health Organization (WHO) from December 1987 until September 2021. To extract these data, VigiBase, the WHO global database of individual case safety reports maintained by the Uppsala Monitoring Centre (UMC), was used. All cases were categorized and analysed and 16 serious cases further assessed. It was concluded that tea tree oil should never be administered orally, as it can lead to central nervous system depression and pneumonitis. Applied topically, skin disorders may occur, especially when the oil had been exposed to light or air. This yields monoterpene oxidation products, being potent skin irritants. Tea tree oil stored under appropriate conditions and not exceeding the expiration date should be considered safe to use by non‐vulnerable people for non‐serious inflammatory skin conditions, although the occurrence of adverse reactions such as contact allergies is difficult to predict.

The Therapeutic Potential of Essential Oils in Managing Inflammatory Skin Conditions: A Scoping Review

“…This leads to the inferior quality of a product upon aging and may be the cause of ADRs associated with their use. A well-known example is oxidation products of terpinene-4-ol in improperly stored or old tea tree oil [68].…”

Deciphering the Broad Antimicrobial Activity of Melaleuca alternifolia Tea Tree Oil by Combining Experimental and Computational Investigations

“…Structures of three most representative TTO compounds (terpinen-4-ol, 1,8-cineol, γ-terpinene) have been retrieved from the PubChem database [59] (https://pubchem.ncbi.nlm.nih.gov/, accessed on 30 November 2022) (Figure S1). The structure of an asymmetric unit of the Coxsackievirus B4 (PDB ID: 6ZMS) [45], selected as a model virus, was superimposed with the Coxsackievirus B3 viral capsid in complex with capsid binder CP17 (PDB ID: 6ZCL) [54], to obtain a final structure composed by 60 repeating asymmetric units each consisting of the four structural proteins, VP1, VP2, VP3 and VP4 (Figure 6A). The asymmetric unit was used as a receptor for molecular docking experiments to check for the possible interactions of TTO molecules within the same binding site of the capsid binders.…”

“…On the other hand, non-enveloped viruses are more resistant than enveloped viruses to antiviral/virucidal treatment with essential oils (EOs), including TTO [40,41,43]. Concerning its toxicity, if correctly used and conserved, TTO can be considered safe [44,45]. Indeed, known adverse reactions are minor, dose dependent, self-limiting and occasional.…”

Effects of adding tea tree oil on growth performance, immune function, and intestinal function of broilers

“…Tea tree oil ( TTO ) is a pure natural plant oil extracted from the stems and leaves of Melaleuca alternifoli ( Bo et al, 2023 ) by steam distillation, which is a colorless to light yellow liquid with a distinctive aromatic odor. Tea tree oil contains a variety of active ingredients, mainly 4-terpineol, 1,8-eudesmanol, and α-pinoresinol ( Bekhof et al, 2023 ). Tea tree oil has been shown to possess several beneficial properties, including anti-inflammatory ( Hart et al, 2000 ), antiviral ( Romeo et al, 2022 ), antitumor ( Clark et al, 2021 ), and antioxidant ( Liu et al, 2022a ) activities.…”