Abstract The steam distilled oil obtained from the berries of Juniperus macrocarpa gathered in the fossil sand dunes of Huelva, southwest Spain, was analyzed by GC and GC/MS in combination with retention indices. The oil contained α-pinene (59.8â70.5%) and myrcene (14.8â15.2%) as major constituents and moderate amounts of γ-muurolene (2.5â5.5%). In addition to these components, minor amounts of β-pinene (2.5â3.4%), limonene (1.1â1.3%), terpinolene (0.9â1.4%), β-caryophyllene (0.4â0.7%), γ-cadinene (0.1â1.1%), δ-cadinene (0.4â1.0%) and α-cadinol (0.2â0.4%) and lower quantities of diterpenes were also identified.