Kairomones are volatile organic compounds (VOCs), produced in air, water or soil by a living being, which trigger a behavioral response in another species, providing a benefit to the latter (e.g. between a plant and an insect).
Allomones are substances produced by individuals of one species, which induce, in those of another species, a reaction favorable to the emitting species. Allomones and kairomones belong to the family of chemical mediators used in biocontrol.