Organic Manuka Honey The valuable honey of the Manuka bush (Leptospermum scoparium), related to the Australian tea tree, is not only used as a luxury item in New Zealand, but also traditionally used externally and internally. It was found that the unique properties of special Manuka honeys are primarily due to the so-called methylglyoxal (MGO), which is contained in this organic Manuka honey with a value of at least 250 mg/kg.