The family Myrtaceae contains many plants, including the Australian tea tree (Melaleuca alternifolia) and its New Zealand equivalents manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides, formerly Leptospermum ericoides). These species have been known collectively as "tea trees" since Captain Cook used their leaves to brew a strong tea for his sailors. Melaleuca alternifolia or "tea tree" is a small tree native to the northeast coastal region of New South Wales, Australia. The leaves are the portion of the plant used medicinally. The medical world's first mention of tea tree appeared in the Medical Journal of Australia in 1930 where a surgeon in Sydney reported some impressive results when a solution of tea tree oil was used for cleaning surgical wounds. Tea tree oil has a broad range of antimicrobial activity.

Although often provided in 100% strength, people with sensitive skin should use it in diluted form. It can be mixed with another oil such as almond oil. If a skin reaction occurs, discontinue use. It has been reported that allergic contact dermatitis to tea tree oil is commonly seen by Australian dermatologists [Medical Journal of Australia, February 21, 1994;160: p.236]. In addition, avoid contact with the eyes and remember to store any product out of the reach of children. Although one Naturopath is known to have swallowed an ounce of tea tree oil daily for thirty days and appeared to show no ill effects, it is generally recommended for external use only.

Tea tree oil has been used in the treatment of: acne, athlete's foot, boils, burns, carbuncles, impetigo, infections of the nail bed, insect bites, ringworm, and vaginal infections. Many products based on tea tree oil exist in the marketplace, including toothpastes, shampoos and conditioners, hand and body lotions, creams, soaps, gels, liniments, and nail polish removers. One study, however, concluded that tea tree oil should not be used on burn wounds. [Burns, 1997;23(4): pp.349-351]

The antimicrobial activity of Manuka honey is discussed in the treatment "Propolis / Bee Products"

Manuka oil has shown some effectiveness in laboratory tests against 39 separate microorganisms, in particular, streptococci and staphylococcal bacteria and fungi that affect the skin.

Gram Positive Bacteria
Staphylococcus aureas
Staphylococcus aureas methacillin resistant
Staphylococcus epidermidis
Streptococcus faecalis
Streptococcus agalactiae
Micrococcus luteus
Sarcina lutea
Bacillus subtilis
Listeria monocytogenes

Gram Negative Bacteria
Escherichia coli
Pseudomonas aeruginosa
Klebsiella pneumoniae
Proteus vulgaris
Vibrio furnissii
Pseudomonas aeruginosa
Pseudomonas fluorscens

Fungi
Trichophyton mentagrophytes
Trichophyton rubrum
Microsporum canis
Aspergillus niger
Candida albicans

Instructions and dosage for Manuka use.
Internally: Adult dose 1-3 drops per day by mouth or inhalation.
Externally: 2-4 drops in the bath or placed directly on affected area.
Mild Sunburn: Apply cold water to remove heat and gently rub Manuka cream into affected areas to help relieve stinging and later itching.
Fungal infections, athletes foot & nail bed infections: Apply a few drops of pure manuka oil with a cotton ball, twice daily. Continue to apply for 5 days after visible signs of infection have gone - which can be a long time, as the nail grows out.
Itching scalp and dandruff: Add 10 drops of pure manuka oil to a normal amount of shampoo and massage into wet hair and scalp. Leave for five minutes before rinsing.
Cuts, scratches and abrasions: Apply pure manuka oil.
Oily skin and pimples: Wash daily with Manuka soap. Apply pure manuka oil as a spot treatment for problem areas.
Skin irritation, chafing and rashes: Wash regularly with Manuka soap and apply Manuka cream twice daily as required.
Foot and body odour: Wash daily with Manuka soap. For foot odour, rub mild Manuka oil or Manuka cream into feet 3 times per week. Also protects against fungal infection.
Insect bites and stings: Apply mild Manuka oil or Manuka cream to help relieve itching and inflammation and prevent infection.