Fumagillin is a potent fungal metabolite first isolated from Aspergillus fumigatus. It is widely used in apiculture and human medicine against a variety of microsporidian fungal infections. It has been the subject of research in cancer treatments by employing its angiogenesis inhibitory properties. The toxicity of fumagillin has limited its use for human applications and spurred the development of analogues using structure-activity relationships relating to its angiogenesis properties. These discoveries may hold the key to the development of alternative chemical treatments for use in apiculture. The toxicity of fumagillin to humans is important for beekeeping, because any residues remaining in hive products pose a direct risk to the consumer. The analytical methods published to date measure fumagillin and its decomposition products but overlook the dicyclohexylamine counterion of the salt form widely used in apiculture.