Juniper berries

Juniper Berries (Juniperus communis L.): A Comprehensive Reference

1. Identity: Botanical Classification, Source, and Forms

Botanical and Chemical Identity

Juniperus communis is a shrub or small evergreen tree, native to Europe, South Asia, and North America, and belongs to the family Cupressaceae. The genus Juniperus includes roughly 68 species and 36 varieties and belongs to the Cupressaceae family. The common names include common juniper and simply juniper. In the European Pharmacopoeia, the plant part was historically described as the "dried ripe cone berry of Juniperus communis L.," designated as Juniperus pseudo-fructus; the most recent edition of the European Pharmacopoeia monograph refers to the plant part as Juniperi galbulus.

The plants bear blue, reddish, or purplish-black fruit described as berries or berry-like cones. The cone is a small, green berry during its first year of growth that turns blue-black during the second year. Importantly, what are colloquially called "berries" are technically fleshy, coalesced seed cones rather than true botanical berries. The plant is native in Europe, West and Central Asia, North Africa and North America.

Juniperus communis is by far the most studied, most commercially available, and most commonly used species, both as food and herbally. Other species, such as Juniperus sabina, are highly toxic and should never be consumed.

Common Forms and Preparations

Juniper is available over the counter as dried berries that can be brewed as tea, berry oil, extract, or tincture, as well as capsule supplements. Essential oil is obtained by steam distillation from the ripe, non-fermented berry cones. In addition to its medicinal uses, dried and crushed juniper berries are used to flavor foods such as meat, soups, sauces, and stews, and certain alcoholic beverages such as beer and gin. Juniper is used as a fragrance in soaps, skin care products, and cosmetics. The essential oil extracted from juniper berries is used in aromatherapy, massage, and during religious ceremonies to purify the air.

Juniper berries and juniper oil have been classified by the EMA's HMPC as traditional herbal medicinal products (Article 16a of Directive 2001/83/EC). Based upon long-standing use, juniper berries and juniper oil can be taken internally to flush the urinary tract as a supportive treatment for minor urinary tract complaints, as well as for dyspeptic complaints and flatulence. Juniper oil is also used externally for mild muscle and joint pain, based upon long-standing use.

2. Traditional and Historical Use

Ancient Egypt

The earliest recorded medicinal use of juniper berries occurs in ancient Egypt. A papyrus dating back to 1500 BC contains a recipe to cure tapeworm infestations. The Romans too used the berries for purification and stomach ailments. Juniper berries, including Juniperus phoenicea and J. oxycedrus, have been found in ancient Egyptian tombs at multiple sites. J. oxycedrus is not known to grow in Egypt, and neither is J. excelsa, which was found along with J. oxycedrus in the tomb of Tutankhamun. The berries imported into Egypt may have come from Greece; the Greeks record using juniper berries as a medicine long before mentioning their use in food.

Ancient Greece and Rome

The Greeks used the berries in many of their Olympics events because of their belief that the berries increased physical stamina in athletes. The Romans also used juniper berries to help aid digestion. In Central European folk medicine, the berries were considered a cure-all for disorders associated with poverty such as typhoid, cholera, dysentery, and tapeworms.

Medieval and Early Modern Europe

The medieval herbalist Culpeper recommended juniper berries for many conditions including flatulence. Juniper was used in the Middle Ages to ward off the plague and in European folk medicine for conditions like arthritis, urinary problems, and as a general tonic. Juniper's use as a fumigant dates back at least to Hippocrates, and it also appears in ethnobotanical records from Ireland, Scotland, and parts of Great Britain. Chemicals in the berries also stimulate contraction of the uterine muscles. They could be administered during labour, but the same properties were also used to abort an unwanted pregnancy. There was a phrase used in Lothian in the Middle Ages of giving birth "under the savin (juniper) tree," which was a euphemism for juniper-induced miscarriage.

Native American Traditions

In the Americas, the Zuni Native Americans used berries to assist them in childbirth, while other Native Americans used juniper berries and leaves to treat infections, arthritis, and wounds. The Blackfoot used juniper berry tea to cure vomiting, while Crow women drank juniper berry tea after childbirth to increase cleansing and healing. In North America, tribes native to the Maritime provinces of Canada used juniper for tuberculosis, ulcers, rheumatism and topically for cuts and wounds. Native Americans also used juniper berries as a female contraceptive, anorexigenic agent, and in the treatment of diabetes.

South and West Asian Traditions

Since ancient times, J. communis parts have been largely used as antiseptics, contraceptives, and diuretics, and as a remedy to treat colds, chest complaints, rheumatism, headaches, dermatological and respiratory ailments, and kidney and urinary infections. Common juniper (Juniperus communis) is traditionally used to treat renal suppression, acute and chronic cystitis, bladder catarrh, albuminuria, leucorrhea, and amenorrhea. It has been used traditionally in the Unani system and in Swedish medicine as a decoction in inflammatory diseases.

Formal Pharmacopoeial Recognition

The herbal substance is mentioned in the DAB 10 (1991), ÖAB 90 (1991), Ph. Fr. X (1996), Ph. Helv. VII (1987), BHP (1983) and the Ph. Eur. 6.0 (2008). The HMPC monograph designates traditional use internally for irrigation of the urinary tract, mild urinary complaints, dyspeptic complaints, and flatulence. The ESCOP monograph covers improvement of renal water excretion and dyspeptic complaints. The German Commission E monograph lists dyspeptic complaints.

3. Key Constituents and Active Compounds

Volatile Essential Oil

As elucidated by GC/FID and GC/MS methods, juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%), and β-pinene (5.0%). The European Pharmacopoeia monograph on Juniperi aetheroleum defines the following characteristic compositional requirements: 20–50% of α-pinene, 1–35.5% of myrcene, less than 20% of sabinene, 2–12% of limonene, 1–12% of β-pinene, less than 7% of trans-(E)-caryophyllene, and 0.5–10% of terpinen-4-ol. Composition can vary considerably by geographic origin and maturity of the cones. Growing region may have an impact on juniper composition and consequent flavor and aroma attributes.

Flavonoids and Polyphenols

The plant contains various chemical constituents including flavonoids, volatile oil, and coumarins. Identified flavonoids include apigenin, rutin, luteolin, quercetin-3-O-arabinosyl-glucoside, quercetin-3-o-rhamnoside (quercitrin), scutellarein, nepetin, amentoflavone, and bilobetin. Biflavones including cupressuflavone, hinokiflavone, isocryptomerin, amentoflavone, and sciadopitysin have also been identified.

Other Chemical Classes

Common juniper berries contain a wide range of biologically active compounds including α-pinene, camphene, pectin, organic acids (glycolic, malic and ascorbic), cyclohexitol, terpenes, proteins, fermentable sugars, wax, gum, cadinene, and juniper camphor. The plant also contains several labdane diterpenes and diterpenoids. The seeds contain haemagglutinin. These uses are mainly attributed to its bioactive composition, which is very rich in phenolics, terpenoids, organic acids, alkaloids, and volatile compounds.

Established Mechanisms of Action

The primary active constituents responsible for pharmacological effects are the monoterpenes, specifically terpinen-4-ol, alpha-pinene, beta-pinene, sabinene, and myrcene. These lipophilic molecules are highly bioavailable and rapidly absorbed across the gastrointestinal mucosa. Terpinen-4-ol is widely considered the most active diuretic and antimicrobial agent within the botanical matrix.

The essential oils in juniper, particularly terpinen-4-ol, are excreted by the kidneys. As they pass through, they mildly irritate the renal tissues, which increases the glomerular filtration rate and urine output.

In addition to the volatile oils, juniper berries contain significant amounts of condensed tannins and flavonoids, such as amentoflavone, quercetin, and isoquercitrin, which contribute to the plant's overall antioxidant capacity and its ability to modulate inflammatory pathways.

Amentoflavone has been determined as a major constituent of berry extracts. The antidiabetic activity of the extracts has been attributed to amentoflavone, which has significant inhibitory activity on carbohydrate digestive enzymes as well as positive effects on insulin resistance.

4. Scientific Evidence by Area of Use

It is important to note at the outset that although juniper has been historically used for many ailments, there are inadequate scientific studies to establish its efficacy in most of its uses. Conclusive evidence supporting the wide array of traditional uses in humans is still lacking. Most published research is based on in vitro assays, animal models, or small preliminary human studies. The following sections characterize the available evidence honestly by strength.

4.1 Diuretic Activity

Traditional and pharmacopoeial basis: The HMPC monograph classifies internal use for irrigation of the urinary tract and mild urinary complaints as traditional use. Contemporary herbalists primarily employ juniper as a diuretic, often combining it with other herbs to potentially enhance its effectiveness against bladder infections.

Evidence: The plant has been reported as diuretic, having anti-inflammatory properties, antifungal activity, analgesic activity, hepatoprotective activity, antidiabetic and antihyperlipidemic activity, antimicrobial activity, and antioxidant activity. Preclinical support comes from animal studies: a study on rats found that juniper berry extract significantly increased urine production. Human evidence remains sparse. The use of juniper as medicine hasn't been studied extensively in humans, so we don't know for sure all that it is capable of. The diuretic mechanism proposed is primarily attributed to renal irritation by terpinen-4-ol, which increases urine flow. Older literature suggests that repeated large doses of juniper volatile oil are associated with nephrotoxic potential; however, animal studies only show toxicity at very high dosages. Case reports of nephrotoxicity are lacking; however, alternative natural medicines are available for diuresis, and juniper should be avoided in renal impairment until definitive studies are available.

Evidence strength: Weak-to-moderate for preclinical (animal) diuretic activity; human evidence is insufficient to draw firm clinical conclusions. The EMA/HMPC classification is "traditional use," not "well-established use," reflecting the absence of adequate clinical trial data.

4.2 Antimicrobial and Antifungal Activity

Evidence: Several reports have highlighted antimicrobial, antifungal, antioxidant, anti-inflammatory and antidiabetic potentials, as well as anticarcinogenic, hepatoprotective, neuronal and renal effects. In vitro laboratory work has been particularly active in this area. Results of an antifungal activity assay (for Aspergillus niger and Penicillium hirsutum) demonstrated inhibition zones of 21.6 mm and 17.2 mm, respectively, for a hydroalcoholic extract of wild-growing J. communis. The European Pharmacopoeia and the official pharmacopeias of Austria and Switzerland recognize the essential oil of J. communis as a treatment for certain bacterial and fungal issues, as well for easing the symptoms of a cold.

Evidence strength: Evidence is predominantly in vitro (cell-based and laboratory assays). There are insufficient randomized human clinical trials to establish clinical antimicrobial efficacy. In vitro results cannot be directly extrapolated to clinical effectiveness.

4.3 Antioxidant Activity

Evidence: The antioxidant capacity of the essential oil has been evaluated in vitro by DPPH scavenging, ABTS radical cation scavenging, hydroxyl radical (OH•) scavenging and chelating capacity, superoxide radical scavenging, and xanthine oxidase inhibitory effects. The antioxidant potential of the crude extract was found to be 81.63 ± 0.38% as measured by the DPPH method in one Romanian study of wild-growing J. communis. Total terpenoids, phenolics, and flavonoids were estimated to be 13.44 ± 0.14 mg linalool equivalent, 19.23 ± 1.32 mg gallic acid equivalent, and 5109.6 ± 21.47 mg rutin equivalent per 100 g of extract, respectively. GC-MS characterization of the juniper extract identified 57 volatile compounds, while HPLC analysis revealed α-pinene, chlorogenic acid, rutin, apigenin, and quercetin.

Evidence strength: Antioxidant activity is well-demonstrated in vitro across multiple assays and model organisms. No large-scale human clinical studies have confirmed clinically relevant antioxidant benefits in vivo.

4.4 Anti-inflammatory Activity

Evidence: The anti-inflammatory effect was evaluated in two experimental models (dextran and kaolin) by plethysmometry. Male Wistar rats were treated by gavage with distilled water (negative control), the microemulsion (positive control), diclofenac sodium aqueous solution (reference), and microemulsions containing juniper extract (experimental group). The initial paw volume and paw volumes at 1, 2, 3, 4, 5, and 24 hours were measured. Animal studies of this type demonstrate anti-inflammatory effects, though the evidence in humans is not established through controlled trials.

Evidence strength: Preclinical (primarily animal model) evidence is moderately consistent; human clinical trials are absent.

4.5 Antidiabetic and Antihyperlipidemic Activity

Evidence: J. communis was reported to have antidiabetic and antihyperlipidemic activity in streptozotocin-nicotinamide-induced diabetic rats. The methanolic extract (100 mg/kg and 200 mg/kg p.o.) was administered compared with glibenclamide (10 mg/kg). Biochemical estimation and fasting blood glucose levels were estimated on the 21st day. The methanolic extract of J. communis mediated significant (P < 0.01) reduction in blood glucose levels and increase in HDL levels in diabetic rats. Glibenclamide showed a significant decrease in the level of SGPT and SGOT. The methanolic extract of J. communis showed significant antidiabetic and antihyperlipidemic activity.

One double-blind, placebo-controlled study suggests juniper may help regulate blood sugar levels, potentially benefiting those with diabetes. Another study indicated juniper may help glycemic control. These human study references are cited in the secondary literature but specific participant numbers and full methodological details require access to primary publications.

In the last few years, several studies have described antidiabetic, antihypercholesterolemic and antihyperlipidemic effects, and neuroprotective action, as well as antiproliferative ability against cancer cells and the ability to activate inductive hepato-, renal- and gastroprotective mechanisms.

Evidence strength: Preclinical (animal) antidiabetic evidence is consistent. Reported human data are very limited, and published double-blind trials have not yet been large or numerous enough to support firm clinical recommendations.

4.6 Antiurolithiatic (Kidney Stone) Activity

Evidence: J. communis berries at concentrations of 500, 1000, and 2000 µg/mL solutions showed potential to dissolve urinary stones brought out from the human kidney, causing reductions of 50, 20, 10, and 20% in urinary stones composed of calcium oxalate, calcium hydrogen phosphate, magnesium ammonium phosphate, and ammonium urate, respectively. This is in vitro/ex vivo evidence only.

Evidence strength: Preliminary in vitro evidence only. No human interventional trials have confirmed these effects in living patients.

4.7 Digestive (Carminative and Stomachic) Activity

Traditionally, juniper has been used for multiple medicinal purposes, including as a carminative, an appetite stimulant, and as a steam inhalant in the management of bronchitis. Prepared extracts of juniper were used to treat snake bites and intestinal worms. The ESCOP monograph covers dyspeptic complaints as a recognized traditional indication. One clinical trial found that juniper extract was effective in reducing symptoms of indigestion and improving gastric function. However, details of this specific trial, including sample size and design quality, are not fully accessible from the sources reviewed.

Evidence strength: Traditional use is well-documented and recognized by official monographs; controlled human trial evidence is minimal.

4.8 Hepatoprotective Activity

Several studies have described a wide range of activities including antimicrobial potential against human pathogens and foodborne microorganisms, notorious antioxidant and anti-inflammatory activities, antidiabetic, antihypercholesterolemic and antihyperlipidemic effects, and neuroprotective action, as well as antiproliferative ability against cancer cells and the ability to activate inductive hepato-, renal- and gastroprotective mechanisms. All evidence for hepatoprotection currently remains at the preclinical level.

Evidence strength: Preclinical only; no human data available.

4.9 Neuroprotective Activity

The plant presents, among other activities, anticataleptic effects and the ability to act as a neuroprotective agent against Parkinson's disease in preclinical models. No human clinical trials have tested these effects.

Evidence strength: Preliminary preclinical evidence only.

5. Body Systems and Health Areas of Association

• Urinary system: Common juniper is traditionally used to treat renal suppression, acute and chronic cystitis, bladder catarrh, and albuminuria. Recognized by HMPC, ESCOP, and Commission E for urinary tract flushing and mild urinary complaints.
• Digestive system: Traditionally used as an antidiarrhoeal, anti-inflammatory, astringent, and antiseptic and in the treatment of various abdominal disorders. Recognized for dyspeptic complaints and flatulence by Commission E and ESCOP.
• Musculoskeletal system: Juniper oil is used externally for mild muscle and joint pain, based upon long-standing use. Used historically for rheumatism, gout, and arthritis.
• Respiratory system: Historically used as a steam inhalant in the management of bronchitis.
• Metabolic/Endocrine system: Investigated preclinically for antidiabetic and antihyperlipidemic effects.
• Immune system: Antimicrobial and antifungal properties documented in vitro; used historically as an antiseptic and fumigant.
• Skin: A poultice of crushed berries or wood has been used to heal wounds, bruises, and other skin conditions.

6. Dosage Forms and Reported Dosages

The following dosages are drawn directly from official monographs and pharmacopoeial references, and are reported only as stated in those sources — they are descriptive, not prescriptive.

Oral Preparations

• Dried fruit (Commission E monograph): The German Commission E monograph suggests ½–2 teaspoons of the dried fruit daily.
• Infusion (tea): 2 to 3 g steeped in 150 mL of boiled water for 20 minutes, three times daily. Drink a cup of juniper berry tea 2 to 3 times per day.
• Whole berries for urinary tract flushing: Starting with 5 berries per day, the dose can be increased by 1 berry per day up to 15 berries per day, then reduced back down to 5 berries per day.
• Capsules or tablets: As a capsule or tablet, 1–2 grams can be taken three times per day.
• Tincture: ¼–½ teaspoon (1–2 mL) of tincture can be taken three times daily. Fluid extract 1:1 (g/mL): 2 to 3 mL three times daily.

External / Topical Use

Herbal preparation in liquid dosage forms for oral and cutaneous use are recognized by the EMA/HMPC monograph. The essential oil is typically diluted in a carrier oil before topical application.

Upper Threshold and Duration

Taking juniper by mouth in doses larger than 10 grams of juniper berries (about 60 berries) or 100 mg of juniper oil, or when used for more than 4 weeks, is likely unsafe.

7. Safety Considerations and Interactions

General Safety Profile

Juniper, juniper berry, and juniper extract are likely safe when consumed in normal food amounts. Juniper is possibly safe for most adults when taken by mouth in medicinal amounts short-term, when inhaled appropriately as a vapor, or when applied to the skin in small areas.

Nephrotoxicity

According to older literature, single, large doses of juniper berries have been reported to cause catharsis, and repeated large doses have been associated with convulsions. Older reports also suggest that juniper volatile oil contains nephrotoxic compounds; however, animal studies only show toxicity at very high dosages. Importantly, one animal study specifically examined this question: the essential oil was evaluated in rats after oral administration. Two slightly different oil batches were tested for 28 days with 100, 333, or 1000 mg/kg, respectively, and terpinene-4-ol was tested at a dosage of 400 mg/kg. Neither of the tested substances induced changes in function or morphology of the kidneys at the tested doses, and they were revealed to be nontoxic. Despite these findings, caution is warranted given the historical concerns, and juniper is noted as contraindicated in kidney diseases.

Pregnancy and Fertility

Juniper is unsafe when taken by mouth during pregnancy or while trying to become pregnant. Juniper has effects that might interfere with fertility or cause a miscarriage. No information is available on the presence of juniper in breastmilk or its effects on breastmilk production or on the breastfed infant. Avoidance is advised if nursing.

Duration Limit

Taking juniper by mouth long-term or in high doses is likely unsafe as it can cause kidney problems, seizures, and other serious side effects. The commonly cited maximum duration is 4 weeks for medicinal use.

Skin and Topical Sensitization

Using juniper on the skin can cause some side effects including irritation, burning, redness, and swelling. Avoidance on large skin wounds is recommended. The additives (juniper oil and tincture) should be considered as irritants to skin and eyes, and as skin and respiratory sensitisers, as noted by the EFSA FEEDAP Panel.

Drug Interactions

Juniper may potentiate or interfere with diuretic therapy. Juniper has diuretic effects, but may cause kidney damage at large doses. Herbs that have a diuretic effect should be avoided when taking diuretic medications, as they may enhance the effect of these drugs and lead to possible cardiovascular side effects.

The coumarin content may interact with anticoagulant medications like warfarin.

Juniper increases effects of antidiabetic agents such as vildagliptin by pharmacodynamic synergism (minor/significance unknown), with a theoretical increased risk of hypoglycemia.

Species Toxicity Caution

Juniperus communis is the species typically used in foods and supplements. Other species, such as Juniperus sabina, are highly toxic and should never be consumed.

Contraindications

Based on official pharmacopoeial and regulatory guidance, the following are recognized contraindications: Juniperus communis L., galbulus is not recommended for patients with conditions where reduced fluid intake is recommended, and is specifically contraindicated in pregnancy and in the setting of renal disease. Diuretic herbal tea combinations must not be used in patients with conditions where a reduced fluid intake is recommended, such as severe heart or kidney disease.

References

• Bais S, Gill NS, Rana N, Shandil S. A Phytopharmacological Review on a Medicinal Plant: Juniperus communis. International Scholarly Research Notices, 2014. PMC4897106
• Falcão S et al. Zimbro (Juniperus communis L.) as a Promising Source of Bioactive Compounds and Biomedical Activities: A Review on Recent Trends. PMC8952110, 2022
• Höferl M et al. Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Antioxidants, 2014. PMC4665443
• Mogoșanu GD et al. Genoprotective, antioxidant, antifungal and anti-inflammatory evaluation of hydroalcoholic extract of wild-growing Juniperus communis L. (Cupressaceae). PMC5755145
• Beyond Essential Oils: Diterpenes, Lignans, and Biflavonoids from Juniperus communis L. as a Source of Multi-Target Lead Compounds. PMC11598787, 2024
• European Medicines Agency (EMA). Juniperi galbulus (pseudo-fructus) – Final EU Herbal Monograph Revision 1. EMA/HMPC/241320/2021
• EMA. Final Assessment Report on Juniperus communis L., pseudo-fructus (galbulus) – Revision 1
• EMA/HMPC. Community Herbal Monograph on Juniperus communis L., aetheroleum. EMA/HMPC/12402/2010
• Altmeyers Encyclopedia – Juniperi fructus (Commission E, ESCOP, HMPC monograph summary)
• Arzneipflanzenlexikon – Juniper: Medicinal Use, Dosage, Side Effects, Interactions
• New World Encyclopedia – Juniper
• Trees for Life – Juniper Mythology and Folklore
• Drugs.com Natural Product Monograph – Juniper
• MedicineNet – Juniper: Herbal Uses, Side Effects, Dosage
• Medscape – Juniperus communis (Juniper) Drug Reference
• Falcão S et al. Chemical Composition and Antimicrobial Activity of Hydrodistilled Oil from Juniper Berries. Industrial Crops and Products, 2018. ScienceDirect
• EFSA FEEDAP Panel. Safety and efficacy of feed additives consisting of essential oil and tincture from Juniperus communis L. EFSA Journal, 2023. PMC10116538
• EBSCO Research Starters – Juniper Berry's Therapeutic Uses
• HealthWise / MaineHealth – Juniper (Commission E dosage reference)
• ScienceDirect Topics – Juniper Berry (Pharmacology and Toxicology)