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MELALEUCA OIL

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Classification   |    Detailed evidence-based information

Substances Included Synonyms

Therapeutic Toxic Class

    A) Melaleuca oil is derived from Melaleuca alternifolia tree. It has been used as a germicidal and for a wide variety of skin complaints. The oil consists of plant terpenes with antimicrobial actions. It is obtained by steam distillation of the leaves which yield about 2% oil.

Specific Substances

    1) Australian Tea Tree Oil
    2) Melaleuca alternafolia oil
    3) Melaleuca alternifolia oil
    4) Oil of melaleuca
    5) Oleum Melaleucae
    6) Tea Tree Oil
    7) CAS 8022-72-8

Available Forms Sources

    A) FORMS
    1) Products containing melaleuca oil have been available as toothpaste, soap, lotion, and skin cream (Anon, 1987).
    B) SOURCES
    1) The tea tree oil consists of terpene hydrocarbons and tertiary alcohols distilled from plantation stands of the plant Melaleuca alternifolia of the Myrtaceae family (Hammer et al, 2006; Anon, 1990; DerMarderosian, 1997; Bassett et al, 1990; Penfold & Grant, 1925; Altman, 1989).
    2) The Australian standard for oil of melaleuca requires that cineole be under 15%, and terpinen-4-ol be over 30%. In practice a 15% cineole and 39% terpinen-4-ol is an inferior oil, with a superior oil having 2.5% and 40% to 47%, respectively (Shemesh & Mayo, 1991).
    C) USES
    1) Melaleuca oil (tea tree oil) has bactericidal and fungicidal properties and is used topically for various ailments (JEF Reynolds , 1999), including acne, boils, burns, corns, gingivitis, herpes, impetigo, insect bites, lice, mouth ulcers, prickly heat ringworm, skin and vaginal infections (Blackwell, 1991), thrush, tinea, and tonsillitis (Altman, 1988).
    2) The oil has been added to baths or vaporizers to help treat respiratory disorders (DerMarderosian, 1997). It has also been used in perfumes and aromatherapy.
    3) HISTORICAL USE: In the early 1900's, tea tree oil was used in surgery and dentistry and for skin injuries (DerMarderosian, 1997).

Overview

Life Support

    A) This overview assumes that basic life support measures have been instituted.

Clinical Effects

    0.2.1) SUMMARY OF EXPOSURE
    A) USES: Melaleuca oil (tea tree oil) is used topically for various ailments, including acne, boils, burns, corns, gingivitis, herpes, impetigo, insect bites, lice, mouth ulcers, prickly heat, ringworm, skin and vaginal infections, thrush, tinea, and tonsillitis.
    B) PHARMACOLOGY: Melaleuca oil (tea tree oil) is derived from Melaleuca alternifolia tree. It is obtained by steam distillation of the leaves which yield about 2% oil. It contains 50% to 60% terpenes (primarily cymene, terpinene, and pinene), cineole (up to 10%) and terpineol. Melaleuca oil has bactericidal and fungicidal properties.
    C) EPIDEMIOLOGY: Exposure is common, but severe toxicity is not anticipated following dermal exposure of low concentrations of tea tree oil.
    D) WITH POISONING/EXPOSURE
    1) MILD TO MODERATE TOXICITY: Overdose data are rare. Topical use of commercially available oil is generally without significant irritant effects. A few cases of allergic dermatitis have been reported following repeated topical application to damaged skin or ingestion. Gastrointestinal distress (eg, abdominal pain, diarrhea) may occur if large amounts are ingested.
    2) SEVERE TOXICITY: CNS depression may occur with ingestion of higher concentrations of tea tree oil. Coma has been reported in an adult. Confusion, incoordination, drowsiness, and ataxia have been reported in children after ingesting up to 10 ml 100% tea tree oil.
    0.2.20) REPRODUCTIVE
    A) At the time of this review, no data were available to assess the teratogenic potential of this agent.
    B) At the time of this review, no data were available to assess the potential effects of exposure to this agent during pregnancy or lactation.
    0.2.21) CARCINOGENICITY
    A) At the time of this review, no data were available to assess the carcinogenic potential of this agent.

Laboratory Monitoring

    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs and mental status.

Treatment Overview

    0.4.2) ORAL/PARENTERAL EXPOSURE
    A) MANAGEMENT OF TOXICITY
    1) Treatment is symptomatic and supportive. Correct any significant electrolyte abnormalities in patients with severe diarrhea.
    B) DECONTAMINATION
    1) PREHOSPITAL: Prehospital gastrointestinal decontamination is generally not recommended because of the potential for CNS depression after ingestion of high concentrations of tea tree oil and subsequent aspiration.
    2) HOSPITAL: GI decontamination is generally not recommended because of the rapid absorption and risk of CNS depression and aspiration.
    C) AIRWAY MANAGEMENT
    1) Ensure adequate ventilation and perform endotracheal intubation early in patients with significant CNS depression or severe allergic reactions.
    D) ANTIDOTE
    1) None.
    E) PATIENT DISPOSITION
    1) HOME CRITERIA: An adult with an inadvertent exposure, that remains asymptomatic can be managed at home. A child who has ingested a high concentration product should be referred to a healthcare facility.
    2) OBSERVATION CRITERIA: Patients who are symptomatic, those with deliberate overdose, and children who have ingested a high concentration product should be observed with frequent monitoring of vital signs. Patients that remain asymptomatic can be discharged.
    3) ADMISSION CRITERIA: Patients who remain symptomatic despite treatment should be admitted.
    4) CONSULT CRITERIA: Consult a poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.
    F) PITFALLS
    1) When managing a suspected overdose, the possibility of multidrug involvement should be considered.
    G) DIFFERENTIAL DIAGNOSIS
    1) Includes other agents that may cause CNS depression.
    0.4.3) INHALATION EXPOSURE
    A) INHALATION: Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with an inhaled beta2-adrenergic agonist. Consider systemic corticosteroids in patients with significant bronchospasm.
    0.4.4) EYE EXPOSURE
    A) DECONTAMINATION: Remove contact lenses and irrigate exposed eyes with copious amounts of room temperature 0.9% saline or water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist after 15 minutes of irrigation, the patient should be seen in a healthcare facility.
    0.4.5) DERMAL EXPOSURE
    A) OVERVIEW
    1) DECONTAMINATION: Remove contaminated clothing and jewelry and place them in plastic bags. Wash exposed areas with soap and water for 10 to 15 minutes with gentle sponging to avoid skin breakdown. A physician may need to examine the area if irritation or pain persists (Burgess et al, 1999).

Range Of Toxicity

    A) TOXICOLOGY: PEDIATRIC: Confusion, incoordination, drowsiness, and ataxia have been reported in children after ingesting less than 10 mL of pure tea tree oil. ADULT: Coma developed in an adult who ingested approximately one-half teacupful.

Clinical Effects

Summary Of Exposure

    A) USES: Melaleuca oil (tea tree oil) is used topically for various ailments, including acne, boils, burns, corns, gingivitis, herpes, impetigo, insect bites, lice, mouth ulcers, prickly heat, ringworm, skin and vaginal infections, thrush, tinea, and tonsillitis.
    B) PHARMACOLOGY: Melaleuca oil (tea tree oil) is derived from Melaleuca alternifolia tree. It is obtained by steam distillation of the leaves which yield about 2% oil. It contains 50% to 60% terpenes (primarily cymene, terpinene, and pinene), cineole (up to 10%) and terpineol. Melaleuca oil has bactericidal and fungicidal properties.
    C) EPIDEMIOLOGY: Exposure is common, but severe toxicity is not anticipated following dermal exposure of low concentrations of tea tree oil.
    D) WITH POISONING/EXPOSURE
    1) MILD TO MODERATE TOXICITY: Overdose data are rare. Topical use of commercially available oil is generally without significant irritant effects. A few cases of allergic dermatitis have been reported following repeated topical application to damaged skin or ingestion. Gastrointestinal distress (eg, abdominal pain, diarrhea) may occur if large amounts are ingested.
    2) SEVERE TOXICITY: CNS depression may occur with ingestion of higher concentrations of tea tree oil. Coma has been reported in an adult. Confusion, incoordination, drowsiness, and ataxia have been reported in children after ingesting up to 10 ml 100% tea tree oil.

Respiratory

    3.6.2) CLINICAL EFFECTS
    A) SUFFOCATING
    1) WITH POISONING/EXPOSURE
    a) This material may present an aspiration hazard when in its pure form. Most commercial products are mixtures with only a small percent of melaleuca oil, thus minimizing the risk.

Neurologic

    3.7.2) CLINICAL EFFECTS
    A) CENTRAL NERVOUS SYSTEM DEFICIT
    1) WITH POISONING/EXPOSURE
    a) CASE REPORTS
    1) PEDIATRIC: Confusion and incoordination developed in a 23-month-old child within 30 minutes of ingesting less than 10 mL of melaleuca oil. No other symptoms were reported. The child received activated charcoal and was asymptomatic 5 hours post ingestion (Jacobs & Hornfeldt, 1994).
    2) PEDIATRIC: A 4-year-old boy also developed ataxia and confusion less than 1 hour after ingesting 2 teaspoons of 100% pure tea tree oil. Vomiting was induced by the parent, which smelled of tea tree oil. Shortly afterwards the child became difficult to arouse, and paramedics intubated the child due to respiratory depression and for airway protection. The child was weaned from the ventilator within a few hours, and was discharged to home within 24 hours with no residual effects (Morris et al, 2003).
    b) ADULT: Coma lasting 12 hours, followed by decreased level of consciousness for 36 hours, has been reported in an adult who ingested approximately one-half teacupful, based on an unpublished report presented at a conference (Seawright, 1993; Carson & Riley, 1995). The dose ingested in this case was estimated as 0.5 to 1 mL/kg body weight (Seawright, 1993; Hammer et al, 2006; Elliot, 1993).
    c) ADULT: More than one ounce of pure oil taken orally has caused CNS depression in an adult, based on anecdotal reports submitted to the manufacturer (Personal Communication, 1991).
    B) ATAXIA
    1) WITH POISONING/EXPOSURE
    a) CASE REPORTS
    1) A 17-month-old boy developed drowsiness and ataxia which lasted less than 5 hours after ingesting less than 10 mL of melaleuca oil (Del Beccaro, 1995).
    2) A 4-year-old boy also developed ataxia and confusion less than 1 hour after ingesting 2 teaspoons of 100% pure tea tree oil. Vomiting was induced by the parent, which smelled of tea tree oil. Shortly afterwards the child became difficult to arouse, and paramedics intubated the child due to respiratory depression and for airway protection. The child was weaned from the ventilator within a few hours, and was discharged to home within 24 hours with no residual effects (Morris et al, 2003).
    3.7.3) ANIMAL EFFECTS
    A) ANIMAL STUDIES
    1) CNS EFFECTS
    a) Topical use of inappropriately high concentrations in dogs, cats and other animals has resulted in ataxia, incoordination, weakness, tremors, altered behavior, and hypersalivation (Villar & Knight, 1994) Bischoff & Gaule, 1998).

Gastrointestinal

    3.8.2) CLINICAL EFFECTS
    A) GASTRITIS
    1) WITH POISONING/EXPOSURE
    a) Gastrointestinal upset may occur if large amounts are ingested. One adult complained of feeling terrible (details not provided) the day after ingesting one-half teaspoonful of melaleuca oil (Elliot, 1993). However, small amounts of the material are taken orally in capsules and as a liquid, usually without significant irritation being reported.
    B) DIARRHEA
    1) WITH POISONING/EXPOSURE
    a) CASE REPORT: Abdominal pain and diarrhea which lasted 6 weeks occurred in an adult who had ingested approximately one-half teacup full of melaleuca oil (Seawright, 1993) .

Genitourinary

    3.10.2) CLINICAL EFFECTS
    A) IRRITATION SYMPTOM
    1) WITH THERAPEUTIC USE
    a) Some cases of vaginal irritation have resulted from therapeutic vaginal use (Anon, 1991).

Dermatologic

    3.14.2) CLINICAL EFFECTS
    A) HYPERSENSITIVITY REACTION
    1) WITH THERAPEUTIC USE
    a) Positive patch test results to a 1% melaleuca oil solution were produced in 7 out of 7 patients who had dermatitis and had repeatedly used concentrated melaleuca oil topically to treat various skin disorders. None of 20 controls responded positively to the 1% melaleuca oil solution (Knight & Hausen, 1994).
    1) D-limonene was the primary constituent of the oil which produced positive patch test responses, followed by aromadendrene and alpha-terpinene. Weaker sensitizers were terpinen-4-ol, p-cymen and alpha-phellandrene (Knight & Hausen, 1994).
    B) CONTACT DERMATITIS
    1) WITH THERAPEUTIC USE
    a) Contact dermatitis was reported in a patient following topical use. The patient had a history of atopy. The actual allergen was eucalyptol (De Groot & Weyland, 1992).
    C) DERMATITIS
    1) WITH THERAPEUTIC USE
    a) CASE REPORT: An erythematous rash on the face, palms, torso, elbows, knees and feet developed a day after an adult ingested approximately one-half teaspoonful of melaleuca oil as a treatment for the common cold. Neither pruritus nor tenderness of the affected skin were reported. Facial, hand, and foot edema were present. A petechial rash and exfoliation developed about 2 days later. The patient had ingested the oil on other occasions, only with occasional itching of the palms (Elliot, 1993).
    b) Ingestion of melaleuca oil in one case reportedly exacerbated dermatitis which had developed as a result of topical application of the oil (Carson & Riley, 1995).
    D) ERUPTION
    1) WITH THERAPEUTIC USE
    a) Facial erythema was noted in a study where the oil was used to treat patients with acne (Selvaag et al, 1994). A similar group of patients, treated with benzoyl peroxide, had slightly less erythema (Bassett et al, 1990).
    E) SKIN IRRITATION
    1) WITH THERAPEUTIC USE
    a) Although irritation is infrequent when applied to the skin, dermal irritation may occasionally occur when melaleuca oil is used topically (Anon, 1991).

Immunologic

    3.19.2) CLINICAL EFFECTS
    A) ACUTE ALLERGIC REACTION
    1) WITH THERAPEUTIC USE
    a) Contact dermatitis was reported in a patient who used the oil topically and who had a history of atopy. The actual allergen was eucalyptol (De Groot & Weyland, 1992). A positive patch test to melaleuca oil and specific constituents of the oil have been reported by other investigators (Knight & Hausen, 1994).
    b) Airborne allergic dermatitis occurred in a male who inhaled the vapors of a hot aqueous solution of tea tree oil for bronchitis (De Groot, 1996). A positive skin test was obtained for several essential oils, including tea tree oil.

Reproductive

    3.20.1) SUMMARY
    A) At the time of this review, no data were available to assess the teratogenic potential of this agent.
    B) At the time of this review, no data were available to assess the potential effects of exposure to this agent during pregnancy or lactation.
    3.20.2) TERATOGENICITY
    A) LACK OF INFORMATION
    1) At the time of this review, no data were available to assess the teratogenic potential of this agent.
    3.20.3) EFFECTS IN PREGNANCY
    A) LACK OF INFORMATION
    1) At the time of this review, no data were available to assess the potential effects of exposure to this agent during pregnancy or lactation.

Carcinogenicity

    3.21.2) SUMMARY/HUMAN
    A) At the time of this review, no data were available to assess the carcinogenic potential of this agent.
    3.21.3) HUMAN STUDIES
    A) LACK OF INFORMATION
    1) At the time of this review, no data were available to assess the carcinogenic potential of this agent.

Laboratory Monitoring

Monitoring Parameters Levels

    4.1.1) SUMMARY
    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs and mental status.

Methods

    A) CHROMATOGRAPHY
    1) The terpine-4-ol can be determined by gas chromatography (Brophy et al, 1989).

Treatment

Life Support

    A) Support respiratory and cardiovascular function.

Patient Disposition

    6.3.1) DISPOSITION/ORAL EXPOSURE
    6.3.1.1) ADMISSION CRITERIA/ORAL
    A) Patients who remain symptomatic despite treatment should be admitted.
    6.3.1.2) HOME CRITERIA/ORAL
    A) An adult with an inadvertent exposure, that remains asymptomatic can be managed at home. A child who has ingested a high concentration product should be referred to a healthcare facility.
    6.3.1.3) CONSULT CRITERIA/ORAL
    A) Consult a poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.
    6.3.1.5) OBSERVATION CRITERIA/ORAL
    A) Patients who are symptomatic, those with deliberate overdose, and children who have ingested a high concentration product should be observed with frequent monitoring of vital signs. Patients that remain asymptomatic can be discharged.

Monitoring

    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs and mental status.

Oral Exposure

    6.5.1) PREVENTION OF ABSORPTION/PREHOSPITAL
    A) Prehospital gastrointestinal decontamination is generally not recommended because of the potential for CNS depression after ingestion of high concentrations of tea tree oil and subsequent aspiration.
    6.5.2) PREVENTION OF ABSORPTION
    A) GI decontamination is generally not recommended because of the rapid absorption and risk of CNS depression and aspiration.
    6.5.3) TREATMENT
    A) SUPPORT
    1) Treatment is symptomatic and supportive. Correct any significant electrolyte abnormalities in patients with severe diarrhea.
    B) MONITORING OF PATIENT
    1) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    2) Monitor vital signs and mental status.

Inhalation Exposure

    6.7.1) DECONTAMINATION
    A) Move patient from the toxic environment to fresh air. Monitor for respiratory distress. If cough or difficulty in breathing develops, evaluate for hypoxia, respiratory tract irritation, bronchitis, or pneumonitis.
    B) OBSERVATION: Carefully observe patients with inhalation exposure for the development of any systemic signs or symptoms and administer symptomatic treatment as necessary.
    C) INITIAL TREATMENT: Administer 100% humidified supplemental oxygen, perform endotracheal intubation and provide assisted ventilation as required. Administer inhaled beta-2 adrenergic agonists, if bronchospasm develops. Consider systemic corticosteroids in patients with significant bronchospasm (National Heart,Lung,and Blood Institute, 2007). Exposed skin and eyes should be flushed with copious amounts of water.

Eye Exposure

    6.8.1) DECONTAMINATION
    A) EYE IRRIGATION, ROUTINE: Remove contact lenses and irrigate exposed eyes with copious amounts of room temperature 0.9% saline or water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist after 15 minutes of irrigation, an ophthalmologic examination should be performed (Peate, 2007; Naradzay & Barish, 2006).

Dermal Exposure

    6.9.1) DECONTAMINATION
    A) DERMAL DECONTAMINATION
    1) DECONTAMINATION: Remove contaminated clothing and wash exposed area thoroughly with soap and water for 10 to 15 minutes. A physician may need to examine the area if irritation or pain persists (Burgess et al, 1999).

Enhanced Elimination

    A) SUMMARY
    1) No studies have addressed the utilization of extracorporeal elimination techniques in poisoning with this agent.

Range Of Toxicity

Summary

    A) TOXICOLOGY: PEDIATRIC: Confusion, incoordination, drowsiness, and ataxia have been reported in children after ingesting less than 10 mL of pure tea tree oil. ADULT: Coma developed in an adult who ingested approximately one-half teacupful.

Maximum Tolerated Exposure

    A) GENERAL
    1) Tea tree oil is a mixture of cyclic hydrocarbons, containing 35% to 40% terpinen-4-ol, 2% to 15% cineole, and other compounds (mostly turpentines and their alcohols). Following ingestion there is a potential risk for aspiration and pneumonitis due to the volatile compounds present (Morris et al, 2003).
    B) CASE REPORTS
    1) CHILD: A 17-month-old boy developed drowsiness and ataxia which lasted less than 5 hours after ingesting less than 10 mL of 100% pure melaleuca oil (Del Beccaro, 1995).
    2) CHILD: Confusion and incoordination developed in a 23-month-old child within 30 minutes of ingesting less than 10 mL of 100% melaleuca oil. No other symptoms were reported. The child received activated charcoal and was asymptomatic 5 hours post ingestion (Jacobs & Hornfeldt, 1994).
    3) CHILD: A 4-year-old boy also developed ataxia and confusion less than 1 hour after ingesting 2 teaspoons (10 mL) of 100% pure tea tree oil. Vomiting was induced by the parent, which smelled of tea tree oil. Shortly afterwards the child became difficult to arouse, and paramedics intubated the child due to respiratory depression and for airway protection. The child was weaned from the ventilator within a few hours, and was discharged to home within 24 hours with no residual effects (Morris et al, 2003).
    4) ADULT: Coma lasting 12 hours, followed by decreased level of consciousness for 36 hours, has been reported in an adult who ingested approximately one-half teacupful, based on an unpublished report presented at a conference. He also developed abdominal pain and diarrhea lasting for 6 weeks (Seawright, 1993; Carson & Riley, 1995). The dose ingested in this case was estimated as 0.5 to 1 mL/kg body weight (Hammer et al, 2006; Elliot, 1993).
    5) ADULT: An erythematous rash on the face, palms, torso, elbows, knees and feet and edema developed a day after an adult ingested approximately one-half teaspoonful (2.5 mL) of melaleuca oil as a treatment for the common cold. A petechial rash and exfoliation developed about 2 days later. The patient had ingested the oil on other occasions, only with occasional itching of the palms (Elliot, 1993).
    C) ANIMAL STUDIES
    1) LD50: oral 1.9 to 2.6 mL/kg. Lethargy and ataxia with depressed activity developed 72 hours after rats were administered oral doses of tea tree oil (1.5 g or less of tea tree oil/kg body weight) (Hammer et al, 2006).

Toxicity Information

    7.7.1) TOXICITY VALUES
    A) LD50- (ORAL)RAT:
    1) 1.9 to 2.6 mL/kg (Hammer et al, 2006)

Pharmacology Toxicology

Pharmacologic Mechanism

    A) INGREDIENTS
    1) Melaleuca oil is a pale yellow oil containing 50 to 60% terpenes (primarily cymene, terpinene, and pinene), cineole (up to 10%) and terpineol (JEF Reynolds , 1999).
    2) There are also a number of other terpenes and some higher alcohols (Williams et al, 1988; (Olsen, 1990).
    3) The active ingredients are thought to be plant terpenes. There are 48 identified compounds isolated so far. The primary ingredient is thought to be terpinen-4-ol (Anon, 1987).
    4) Terpinen-4-ol has been associated with improved skin healing when used in a 30% concentration (Anon, 1991).
    B) EFFICACY
    1) Although recommended for various skin and mucous membrane ailments (Penfold, 1937; Altman, 1989), well controlled clinical studies are generally lacking. Much of the information available was done 50 or more years ago.
    a) VAGINALLY: An isopropyl alcohol and 40% tea oil emulsion, as well as a 1% solution were found effective when used as a vaginal douche against trichomonal cervicitis (Pena, 1962).
    1) Vaginal candidiasis and bacterial vaginosis were successfully treated with vaginal suppositories/pessaries containing the oil (Belaiche, 1985; Blackwell, 1991).
    b) ORAL: Capsules of the oil taken daily demonstrated a slight clinical effect by improving chronic cystitis in 7 of 13 patients (Olsen, 1990).
    c) TOPICALLY
    1) The oil has an MIC (v/v) of 0.5% for Aspergillus niger, 0.75% for Trichophyton mentagrophytes, 0.5% for Trichophyton rubrum, 0.75% for P. acnes, 0.63% for Staphylococcus aureus, 0.25% for Aspergillus flavus, 0.63% for Escherichia coli, and 0.63% for Candida albicans (Olsen, 1990; Bassett et al, 1990).
    2) It has been used in the treatment of athlete's foot, corns, and skin infections (Belaiche, 1985a; Walker, 1972).
    3) Effectiveness of individual products may vary because the available oils are sometimes diluted with other volatile oils (Anon, 1991).
    d) HISTORICAL DATA
    1) DENTAL: Australian dentists were using the oil as an antiseptic in the 1930's (Penfold & Morrison, 1930).

Physicochemical

Physical Characteristics

    A) A pale yellow oil with a pleasant characteristic odor and a terebinthinate taste obtained by distillation from the leaves of the Australian tea tree, melaleuca alternifolia (JEF Reynolds , 1999; Olsen, 1990).

Molecular Weight

    A) Not available

Animal Toxicology

Clinical Effects

    11.1.3) CANINE/DOG
    A) Anecdotal reports to the manufacturer have implied that when the pure oil was applied topically and externally to the spinal column of a small dog, paralysis occurred (Personal Communication, 1991).
    B) Topical use of inappropriately high concentrations in dogs, cats and other animals has resulted in ataxia, incoordination, weakness, tremors, altered behavior, and hypersalivation. Symptom onset is usually between 2 and 8 hours, but has occurred within minutes in kittens which were dipped in a melaleuca oil-containing product (Villar & Knight, 1994; Bischoff & Guale, 1998).
    C) Ingestion (including that which may occur during grooming) may also cause toxicity (Villar & Knight, 1994).
    11.1.6) FELINE/CAT
    A) Topical use of melaleuca alternifolia oil (product contained 100% of the oil) resulted in toxicity and death in 1 of 3 cats exposed (Bischoff & Guale, 1998).
    1) Hypothermia was observed within 5 hours of application in one cat; the other two cats were admitted the next day. Cat 2 developed coma and severe hypothermia while cat 3 was alert, but exhibited CNS effects which included nervousness, slight ataxia, and trembling.

Treatment

    11.2.2) LIFE SUPPORT
    A) GENERAL
    1) MAINTAIN VITAL FUNCTIONS: Secure airway, supply oxygen, and begin supportive fluid therapy if necessary.
    11.2.5) TREATMENT
    A) GENERAL TREATMENT
    1) No specific antidote is available (Villar & Knight, 1994).
    2) DERMAL EXPOSURE - Bathe the animal with a mild, non-insecticidal shampoo in order to remove the oil. Monitor vital signs. Treat hypothermia. Administer isotonic IV fluids and glucose, as needed (Villar & Knight, 1994; Bischoff & Guale, 1998).
    a) CASE REPORT - Topical use of the oil (product contained 100% melaleuca alternifolia) resulted in toxicity and death in 1 of 3 purebred cats (Bischoff & Guale, 1998).
    1) Decontamination included oral activated charcoal, as well as, dermal decontamination with soap and water.
    2) Treatment included isotonic saline IV for rehydration. Hypothermia was treated with heat lamps and warm water bottles. Two of the three cats recovered without sequelae 48 and 72 hours, respectively, after exposure; one cat died with the cause of death unknown.
    3) INGESTION - Activated charcoal and a cathartic may decrease systemic absorption and increase elimination of melaleuca oil (Villar & Knight, 1994). Monitor vital signs, treat hypothermia and administer IV fluids and glucose, as needed.

References

General Bibliography

    1) Altman PM: Australian tea tree oil. Aust J Pharm 1988; 69:276-278.
    2) Altman PM: Australian tea-tree oil - a natural antiseptic. Aust J Biotechnol 1989; 3:247-248.
    3) Anon: Australian Tea Tree. Lawrence Rev of Nat Prod (January), 1991.
    4) Anon: Melaleuca estates' tea tree oil will receive $50,000 NIH grant. US FDC Reports (Feb 16), 1987.
    5) Anon: Tea-tree oil and acne. Lancet 1990; 336:1438.
    6) Bassett IB, Pannowitz DL, & Barnetson RSC: A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne. Med J Aust 1990; 153:455-457.
    7) Belaiche P: Treatment of skin infection with the essential oil of Melaleuca alternifolia. Phylotherapie 1985a; 15.
    8) Belaiche P: Treatment of vaginal infections of Candida albicans with the essential oil of Melaleuca alternifolia. Phylotherapie 1985; 15.
    9) Bischoff K & Guale F: Australian tea tree (Melaleuca alternifolia) oil poisoning in three purebred cats. J Vet Diagn Invest 1998; 10:208-210.
    10) Blackwell AL: Tea tree oil and anaerobic (bacterial) vaginosis (letter). Lancet 1991; 337:300.
    11) Brophy JJ, Davies NW, & Sothwell IA: Gas chromatographic quality control for oil of Melaleuca terpine-4-ol type (Australian tea tree). J Agric Food Chem 1989; 37:1330-1335.
    12) Burgess JL, Kirk M, Borron SW, et al: Emergency department hazardous materials protocol for contaminated patients. Ann Emerg Med 1999; 34(2):205-212.
    13) Carson CF & Riley TV : Toxicity of the essential oil of Melaleuca alternifolia or tea tree oil. J Toxicol Clin Toxicol 1995; 33(2):193-194.
    14) De Groot AC & Weyland JW: Systemic contact dermatitis from tea tree oil. Contact Dermatitis 1992; 27:279-208.
    15) De Groot AC: Airborne allergic dermatitis from tea tree oil. Contact Dermatitis 1996; 35:304-305.
    16) Del Beccaro MA: Melaleuca oil poisoning in a 17-month-old. Vet Human Toxicol 1995; 37:557-558.
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