Mānuka honey is a monofloral honey produced in New Zealand and Australia from the nectar of the mānuka tree. It has in vitro antibacterial properties, but there is not conclusive evidence of benefit in medical use. It has been classified as a Therapeutic Good in Australia, and has received approval from the US Food and Drug Administration in 2007.
Mānuka honey is produced by introduced European honey bees (Apis mellifera) feeding on the mānuka or tea tree (Leptospermum scoparium and/or Leptospermum polygalifolium), which grows uncultivated throughout New Zealand and southeastern Australia.
Mānuka honey is markedly thixotropic and has shown the highest viscosity among a range of studied honeys. This property is due to the presence of a protein or colloid and is its main visually defining character, along with its typical dark cream to dark brown colour. To be labelled mānuka honey, at least 70% of its pollen content should come from Leptospermum scoparium.
The mānuka tree flowers more or less at the same time as Kunzea ericoides, another Myrtaceae species also called Kānuka, which often shares the same growing areas as the former species. Some apiarists cannot readily differentiate these two species from each other. Both flowers have a similar morphology and pollen differentiation between the two species is very difficult. Therefore, melissopalynology as identification for the type of honey is valid only in association with other identification tests. In particular, L. scoparium honey is dark, whereas K. ericoides honey is pale yellow and clear, with a "delicate, sweet, slightly aromatic" aroma and a "sweet, slightly aromatic" flavour, and is not thixotropic.
Heather (Calluna vulgaris) honey is also thixotropic, but the plant flowers in late summer and its montane distribution area does not correspond with that of Leptospermum scoparium. Therefore, its harvest cannot be mistaken for that of manuka honey.
Manuka honey has a strong flavour, which has been characterized as, "earthy, oily, herbaceous", and "florid, rich and complex". Other qualificatives used by the New Zealand honey industry are, a "damp earth, heather, aromatic" aroma and a "mineral, slightly bitter" flavour.
Medicinal properties 
A 2002 review found that although the antibacterial activity of honeys (including mānuka honey) had been demonstrated in vitro, the number of clinical case studies was small. The review concluded that there was a potential for its use in "the management of a large number of wound types". A 2008 Cochrane Review found that honey may help improve superficial burns compared to standard dressing, but there was insufficient evidence from studies, many of which were on mānuka honey, to be conclusive, and the use of honey for leg ulcers provided no benefit. The review found that there was insufficient evidence for any benefit in other types of chronic wounds, as all of the data came from a single centre of research, and that "data from trials of higher quality found honey had no significant effect on healing rates or had significantly slower rates of healing".
Methylglyoxal (MGO) is the major antibacterial component of mānuka honey. Other smaller antibacterial effects are expected to arise from the osmolarity and pH of the mānuka honey. In vitro studies indicate methylglyoxal is an effective antimicrobial agent against forms of MRSA, although studies have not been done in humans.
See also 
- Honey-Based Dressings and Wound Care: An Option for Care in the United States. Pieper, Barbara. Journal of Wound, Ostomy & Continence Nursing: January/February 2009 - Volume 36 - Issue 1 - p 60–66.
- Jon Morgan (5 March 2009). "Money from honey - a family affair". Dominion Post. Retrieved 12 March 2011.
- The factors responsible for the varying levels of UMF® in mānuka (Leptospermum scoparium) honey. Jonathan McD C Stephens. Doctorate thesis. 2006.
- Julie Biuso, Sizzle: Sensational Barbecue Food, Monterey, Cal.: Julie Biuso Publications, 2008, p. 154
- Crescent Dragonwagon, Passionate Vegetarian, New York: Workman Publishing Co., 2002, p. 958
- Lusby, PE; Coombes, A, Wilkinson, JM (2002 Nov). "Honey: a potent agent for wound healing?". Journal of wound, ostomy, and continence nursing: official publication of The Wound, Ostomy and Continence Nurses Society / WOCN 29 (6): 295–300. doi:10.1067/mjw.2002.129073. PMID 12439453.
- Jull, AB; Rodgers, A, Walker, N (2008 Oct 8). "Honey as a topical treatment for wounds.". Cochrane database of systematic reviews (Online) (4): CD005083. doi:10.1002/14651858.CD005083.pub2. PMID 18843679.
- Majtan, J; Klaudiny, J, Bohova, J, Kohutova, L, Dzurova, M, Sediva, M, Bartosova, M, Majtan, V (2012 Feb 17). "Methylglyoxal-induced modifications of significant honeybee proteinous components in manuka honey: Possible therapeutic implications.". Fitoterapia 83 (4): 671–7. doi:10.1016/j.fitote.2012.02.002. PMID 22366273.
- Kilty, S. J.; Duval, M.; Chan, F. T.; Ferris, W.; Slinger, R. (2011). "Methylglyoxal: (active agent of manuka honey) in vitro activity against bacterial biofilms". International Forum of Allergy & Rhinology 1 (5): 348–350. doi:10.1002/alr.20073. PMID 22287464.
- Mavric, E.; Wittmann, S.; Barth, G.; Henle, T. (2008). "Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium)honeys from New Zealand". Molecular Nutrition & Food Research 52 (4): 483–489. doi:10.1002/mnfr.200700282. PMID 18210383.
- Eekhof, JA; Van Wijk, B, Knuistingh Neven, A, van der Wouden, JC (2012 Apr 18). "Interventions for ingrowing toenails.". Cochrane database of systematic reviews (Online) 4: CD001541. doi:10.1002/14651858.CD001541.pub3. PMID 22513901.
- What's special about Active Manuka Honey? from Waikato Honey Research Unit
- "Honey can reverse antibiotic resistance, study suggests". Science Daily. 13 April 2011.
- Published clinical data Information with references supplied by Advancis Medical Ltd