Germacrenes are a class of volatile organic hydrocarbons, specifically, sesquiterpenes.

Germacrenes are typically produced in a number of plant species for their antimicrobial and insecticidal properties, though they also play a role as insect pheromones.

Two prominent molecules are germacrene A and germacrene D. Germacrene has five isomers.

The essential oils of red deadnettle (Lamium purpureum)[1] and hedgenettles (genus Stachys)[2] are characterized by their high contents of germacrene D, as is Clausena anisata.

It is also a major component of patchouli oil.