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.
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.
Dried ripe berries: 1 to 2 g by mouth three times a day; maximum 10 g dried berries daily, equaling 20 to 100 mg essential oil
Liquid extract (1:1 in 25% alcohol): 2 to 4 ml by mouth three times a day
Oil (1:5 in 45% alcohol): 0.03 to 0.2 ml by mouth three times a day
Tea (steep 1 teaspoon crushed berries in 5 oz boiling water for 10 minutes, and then strain): three times a day
Tincture (1:5 in 45% alcohol): 1 to 2 ml by mouth three times a day.
Adverse reactions to juniper include local irritation and metrorrhagia. When used with antidiabetics such as chlorpropamide, glipizide, and glyburide, hypoglycemic effects may be potentiated. Concomitant use of juniper and anti-hypertensives may interfere with blood pressure. Juniper may potentiate the effects of diuretics such as furosemide, leading to additive hypokalemia. A disulfiram-like reaction could occur because of alcohol content of juniper extract.
There may be additive hypoglycemic effects when juniper is combined with other herbs that lower blood glucose level, such as Asian ginseng, dandelion, fenugreek, and Siberian ginseng. Juniper may have additive effects with other herbs causing diuresis, such as cowslip, cucumber, dandelion, and horsetail.
Women who are pregnant or breast-feeding should avoid juniper because of its uterine stimulant and abortifacient properties. Juniper shouldn’t be used by those with renal insufficiency, inflammatory disorders of the GI tract (such as Crohn’s disease), seizure disorders, or known hypersensitivity. It shouldn’t be used topically on large ulcers or wounds because it may cause local irritation.
Safety Risk Juniper may cause seizures, kidney failure, and spontaneous abortion.
Advise patient that he shouldn’t take juniper preparations for longer than 4 weeks.
Overdose of juniper may cause seizures, tachycardia, hypertension, and renal failure with albuminuria, hematuria, and purplish urine. Monitor blood pressure and potassium, BUN, creatinine, and blood glucose level.
Warn patient not to confuse juniper with cade oil, which is derived from juniper wood.
Advise female patient to report planned or suspected pregnancy before using juniper.
Inform patient that urine may turn purplish with higher doses of juniper.
Tell patient to avoid applying juniper to large ulcers or wounds because local irritation (burning, blistering, redness, and edema) may occur.
Caution against using alcohol while taking juniper.
Recommend that patient seek medical diagnosis before taking juniper. Unadvised use of juniper could worsen urinary problems,
Tell patient to notify pharmacist of any herbal and dietary supplements that he’s taking when obtaining a new prescription.
Advise patient to consult his health care provider before using an herbal preparation because a conventional treatment with proven efficacy may be available.
Safety Risk Kidney damage may occur in patients taking juniper for extended periods. This effect may stem from prolonged kidney irritation caused by terpinene-4-ol or by tur pentine oil contamination ofjuniper products.
Juniper may have some benefit in diabetic treatment, but further study is necessary. Juniper has an extensive toxicology profile, and therefore must be used with caution.