Exopheromone is a term coined by Terence McKenna, proposed in his book Food of the Gods for the controversial idea of chemical signals between members of different classes of living things, as opposed to among conspecifics. He suggested that certain chemicals produced in abundance in various hallucinogenic plants and fungi, such as dimethyltryptamine and psilocybin may act as pheromones produced by one kingdom (the vegetal) waiting for absorption by various others (for example, early primates or hominids).
Terence McKenna's term "exopheromone" was introduced in his book "Food of the Gods," proposing an unconventional idea about chemical signals between different species, as opposed to within the same kind. He suggested that certain chemicals found in hallucinogenic plants and fungi might function as pheromones facilitating communication across kingdoms.