Honey's been used as a medicine for centuries, due to its antibacterial, anti-inflammatory, and antioxidant properties—all of which are related to the nectar the bees gather, which can vary plant by plant.
As for manuka honey specifically: According to Sharon Palmer, RDN, author of Plant-Power for Life, manuka comes from New Zealand, where it's made by bees that pollinate the flowers of the local, native manuka bush.
"Manuka honey has high concetrations of compounds with antibacterial activity," says Palmer. "There's even a grading system for manuka, called UMF, which scores quality." 16-plus means the honey is of premium purity, but avoid manuka graded lower than 10.
And while manuka's been hyped with mostly baseless claims that it cures everything from cancer to diabetes, says Palmer, one study did conclude that it can fight gum disease.
So consider manuka honey a sweetener with potential health benefits—but not a magic bullet.