The fruits of J. communis are berries, green the first year ripening to black in the second or third year. This species is the most widely distributed conifer in the world and the most widespread tree species in the North Temperate zone.
Volatile oil is found in highest concentration in full-grown but unripe berries.
You should obtain 0.5 ml. of juniper oil from each 100 grams of berries. The riper the berries, the more of the volatile oil has been converted to resin. The volatile oil has been called oil of sabinal. The fruit also contains resin, sugar, tannin, and a flavone of glycoside. The Merck Index cites juniperin as a constituent.