Tea tree oil

Although tea tree oil is claimed to be useful for treating dandruff, acne, lice, herpes, insect bites, scabies, and skin fungal or bacterial infections, and while evidence exists to support some of these claims, there are a limited number of research studies. Tea tree oil was also used during World War II to treat skin lesions of munitions factory workers. Tea tree oil is not recommended for treating nail fungus because it is yet to be proven effective, It is not recommended for treating head lice in children because its effectiveness and safety have not been established and it could cause skin irritation or allergic reactions. Tea tree oil is one of many natural products promoted as a treatment for demodex mite infestations, but there is uncertainty about the effectiveness of 5-50% solution, and any overall effectiveness is offset by unwanted adverse effects and toxicity. Tea tree oil exhibits anti-microbial, anti-fungal and antibacterial properties. == Toxicity ==

Tea tree oil is highly toxic when ingested orally. It may cause drowsiness, confusion, hallucinations, coma, unsteadiness, weakness, vomiting, diarrhoea, nausea, blood-cell abnormalities, and severe rashes. It should be kept away from pets and children. Application of tea tree oil to the skin can cause an allergic reaction in some, Adverse effects include skin irritation, allergic contact dermatitis, systemic contact dermatitis, linear immunoglobulin A disease, erythema multiforme-like reactions, and systemic hypersensitivity reactions. Allergic reactions may be due to the various oxidation products that are formed by exposure of the oil to light and air. Consequently, oxidised tea tree oil should not be used. In Australia, tea tree oil is one of the many essential oils causing poisoning, mostly of children. From 2014 to 2018, 749 cases were reported in New South Wales, accounting for 17% of essential oil poisoning incidents. Hormonal effects Tea tree oil potentially poses a risk for causing abnormal breast enlargement in men and prepubertal children. A 2018 study by the National Institute of Environmental Health Sciences found four of the constituent chemicals (eucalyptol, 4-terpineol, dipentene, and alpha-terpineol) are endocrine disruptors, raising concerns of potential environmental health impacts from the oil. In animals In dogs and cats, death or transient signs of toxicity (lasting two to three days), such as lethargy, weakness, incoordination, and muscle tremors, have been reported after external application at high doses. As a test of toxicity by oral intake, the median lethal dose (LD50) in rats is 1.9–2.4 ml/kg. ==Composition and characteristics==

Tea tree oil is defined by the International Standard ISO 4730 ("Oil of Melaleuca, terpinen-4-ol type"), containing terpinen-4-ol, γ-terpinene, and α-terpinene as about 70% to 90% of whole oil, while p-cymene, terpinolene, α-terpineol, and α-pinene collectively account for some 15% of the oil (table). Tea tree oil products contain various phytochemicals, among which terpinen-4-ol is the major component. Adverse reactions diminish with lower eucalyptol content. == History and extraction ==

The name "tea tree" is used for several plants, mostly from Australia and New Zealand, from the family Myrtaceae related to the myrtle. The use of the name probably originated from Captain James Cook's description of one of these shrubs that he used to make an infusion to drink in place of tea. The commercial tea tree oil industry originated in the 1920s when Australian chemist Arthur Penfold investigated the business potential of a number of native extracted oils; he reported that tea tree oil had promise, as it exhibited antiseptic properties. Tea tree oil was first extracted from Melaleuca alternifolia in Australia, and this species remains the most important commercially. In the 1970s and 1980s, commercial plantations began to produce large quantities of tea tree oil from M. alternifolia. Many of these plantations are located in New South Wales.). Similar oils can also be produced by water distillation from Melaleuca linariifolia and Melaleuca dissitiflora. Whereas the availability and nonproprietary nature of tea tree oil would make it – if proved effective – particularly well-suited to a disease such as scabies that affects poor people disproportionately, those same characteristics diminish corporate interest in its development and validation. == See also ==