Juniper berries have long been used as a flavoring in foods and alcoholic beverages such as gin. Gin's original preparation was used for kidney ailments. Immature berries are green, taking 2 to 3 years to ripen to a purplish blue-black. The active component is a volatile oil, which is 0.2% to 3.4% of the berry. The best described effect is diuresis, caused by terpinene-4-01, which results from a direct irritation to the kidney, leading to increased glomerular filtration rate. Juniper berries are available as ripe berry, also called berry-like cones or mature female cones, fresh or dried, and as powder, tea, tincture, oil, or liquid extract.

Reported uses

Juniper berries are used to treat urinary tract infections and kidney stones. They're also used as a carminative and for multiple nonspecific GI tract disorders, including dyspepsia, flatulence, colic, heartburn, anorexia, and inflammatory GI disorders.

Juniper berries may be applied topically to treat small wounds and relieve muscle and joint pain caused by rheumatism. The fragrance is inhaled as steam to treat bronchitis. The oil is used as a fragrance in many soaps and cosmetics. Juniper berries are the principle flavoring agent in gin, as well as some bitters and liqueurs.

As a food, maximum flavoring concentrations are 0.01% of the extract or 0.006% of the volatile oil. Other reported effects of juniper include hypoglycemia, hypotension or hypertension, anti-inflammatory and antiseptic effects, and stimulation of uterine activity leading to decreased implantation and increased abortifacient effects.