(E)-2-decenoic acid is a stereoisomer of the corresponding medium-chain fatty acid in the trans configuration. This compound excreted by the caries bacterium Streptococcus mutants and inhibits the morphological transition from yeast to hyphae, an important virulence trait, in the opportunistic fungus Candida albicans. As a component of royal jelly it exhibits estrogenic effect by activation of estrogen receptor beta. Ethyl ester of trans-2-decenoic acid exerts neurotrophin-like neurotrophic activities in animal models of stress-induced anxiety-like, cerebral infarction and spinal cord injury.