MGO stands for Methylglyoxal, which is a naturally occurring compound found only in Manuka honey. It is the compound associated with Manuka honeys unique antibacterial properties and is responsible for its non-peroxide activity. The MGO rating on a jar of Manuka honey indicates its content, and the higher the rating, the more Methylglyoxal in that batch. The MGO rating shows the amount of Methylglyoxal in the honey, measured in milligrams per kilogram of Manuka honey. The concentration of MGO in Manuka honey can be around 100 times higher than in other types of honey. MGO is one of the factors that contribute to Manuka honeys unique health benefits, and some scientists believe that it acts as a natural type of antibiotic. The MGO rating is one of the industry-accepted ratings, and some Manuka honey producers use a UMF rating instead of the MGO rating.