Is Juniper Toxic?
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I can still clearly recall my first couple experiences with juniper as a green and eager forager. I had been familiar with the plant since early childhood, frequently plucking the tips of the leaves and crushing them between my fingers to inhale the uplifting aroma. When I started a regular foraging practice at the age of 19, I read about using juniper berries and leaves as a seasoning and for medicinal purposes. Several months later I contracted a UTI and remembered reading that juniper functions as a urinary cleanser. I made tea from the leaves of a local tree, and with the help of cranberry juice, my UTI cleared up in a few days. It felt empowering to me at the time and greatly increased my appreciation for juniper.
A handful of common juniper (Juniperus communis) berries
I enjoyed the flavor and made a semi-regular practice of picking juniper berries and leaves for culinary and medicinal purposes. Herbal medicine books urged a light hand, noting that it can be toxic with frequent or heavy use. Many books mentioned a contraindication with kidney disease. Therefore I never used it frequently. It wasn’t until recently that I learned that these warnings are likely conflating a known toxic species of juniper (Juniperus sabina) with edible varieties. Furthermore, I was accustomed to indiscriminately picking any species of juniper, not realizing that certain species should be avoided. While I haven’t completely untangled the mystery regarding juniper toxicity, I have learned quite a bit and share it below to help end misinformation on the subject.
Wild Edible Trees Workshop
If you live in the Minneapolis, Minnesota area and want to learn more about juniper species, I recommend joining my Wild Edible Trees workshop this Saturday! We will discuss a wide diversity of tree species on the landscape, including juniper.
What is Juniper?
Eastern red cedar (Juniperus virginiana) twigs and berries
The common name “juniper” encompasses many plants in the Juniperus genus. There are approximately 60 species of juniper found around the world, and about 30 are found in North America (including hybrids and cultivars.) Minnesota has three native species: common juniper (J. communis), eastern red cedar (J. virginiana) and creeping juniper (J. horizontalis), which is a species of special concern in the state. Common juniper has the widest range of all the junipers, and perhaps of any woody plant in the northern hemisphere. In North America, it grows from the Arctic to higher elevations as far south as Arizona and New Mexico; it also grows across Europe and Asia south to the Mediterranean and Nepal.
Junipers are evergreen conifers with modified cones that look like berries. In Minnesota, the “berries” of all species are dark blue at maturity. The foliage can be scale-like or needle-like, depending on the species. Some species have both scale-like and needle-like leaves, where the young growth is sharp and pointed and becomes flattened and scaley with maturity. Some junipers grow as shrubs, while others are small trees, and still others grow into tall trees.
Here follow some short descriptions of Minnesota species. Please reference a trusted field guide or online resource (such as Minnesota Wildflowers) for more detail. Common juniper is a shrub that grows up to 5 feet tall and 20 feet across, while red cedar is a small to midsize tree with a conical crown. Common juniper has sharp-pointed leaves (needles) in whorls of three, and those of red cedar are opposite in twos and scalelike. However, the juvenile growth is needle-like. Creeping juniper leaves and berries look very similar to those of red cedar; but as its name implies, it grows low to the ground, rarely exceeding heights of 10 inches.
Eastern red cedar twig showing immature needle-like leaves
Toxic Juniper
There are certainly toxic species of juniper that should be avoided for edible and medicinal purposes, and it should definitely not be assumed that all members of the genus can be used similarly. Savin juniper (Juniperus sabina) is probably the best documented. The book Witchcraft Medicine by Christian Rätsch, Claudia Müller-Ebeling, and Wolf-Dieter Storl states, “Since antiquity it has been considered one of the most powerful and effective natural abortifacients. However, the use of the branch tips or top shoots of savine for abortion is not entirely without danger. A decoction of 50 to 60 grams of the tips causes a strong rush of blood in the abdomen, urinary tract infections, and abortions and can also lead to fatal poisoning.” (page 123) The “Juniperus Species” chapter of Adverse Effects of Herbal Drugs 2 says that “as little as six drops [of oil from J. sabina] can be toxic” and “Manceau et al report that several grams of savin will kill a dog.” (page 221) The Monaco Nature Encyclopedia has a thorough description of savin juniper, including toxicity and symptoms of poisoning. It states “The symptoms of the low dosage intoxication consist in irritation of the mouth, diarrhoea, vomit, colics. High doses cause serious poisoning, with tachycardia, breathing difficulties, cramps, paralysis, coma and death in the 50% of the cases. Due to the high toxicity, in many countries the sale of the oil has been forbidden.”
Though savin juniper is native to the mountains of central and southern Europe and western and central Asia, it is a popular ornamental shrub and there are numerous cultivars. It is therefore imperative to exercise caution when harvesting juniper from cultivated landscapes such as yards, parks, and boulevards.
Savin juniper (Juniperus sabina) planted in a yard.
Edible and Medicinal Juniper
Some sources recommend only consuming common juniper, which has a long history of use for culinary and medicinal purposes across many cultures. (See for example Latifa’s Herbs.) Sam Thayer’s Field Guide to Edible Wild Plants lists common juniper and eastern red cedar as edible. He states that berries can be consumed from both species, while tender branch tips and needles should be restricted to common juniper. “Because there are some known species of juniper with mildly toxic needles, and I am not aware of any food tradition using redcedar needles, I advise against using them for tea or seasoning.” (page 65) Still other sources list the leaves of eastern red cedar as medicinal. (See for example the Indigenous Peoples’ Perspective Project and Lindsay Kolasa.)
I leave it up to you to decide which species you want to consume (if any). For me personally, I am comfortable using the berries and leaves of both common juniper and eastern red cedar for edible and medicinal purposes. I have been eating both species for over twenty years and have never had adverse reactions. That said, only small amounts are required when used as a seasoning, and my medicinal use of the plants has always been limited to brief periods.
So how does one consume juniper? There is a long history all around the world of using juniper berries in tea, as a seasoning, in spirits, and more. Gin is the most famous of these—a hard alcohol flavored with juniper and other botanicals. But there are others, including borovička (a juniper spirit or juniper brandy from Slovakia and the Czech Republic) and smreka (a fermented juniper drink from the Balkan region.) Juniper as a seasoning is traditional in sauerkraut, sausage, fish, and can be infused into butter and yogurt for delicious spreads and sauces. It can also be infused into syrup, sugar, or salt; and dried and burned to make culinary ash. The options seem endless once you start looking into it!
Making DIY gin with common juniper berries and other botanicals
The medicinal uses of juniper are similarly diverse, owing to its wide-ranging use. Common juniper berries are used in traditional Turkish medicine as a diuretic, for gastrointestinal problems, and as a general antiseptic. They are also used for the treatment of rheumatism, arthritis, and gout, and are believed to have both anti-inflammatory and analgesic effects. Some Native American tribes used common juniper berries as an appetite suppressant and in the treatment of diabetes. Hypoglycemic/anti-diabetic effects have been demonstrated in several laboratory studies. Further studies report strong antioxidant activity for common juniper berries. The essential oils have been shown to be anti-bacterial against several pathogenic strains, including Escherichia coli and Listeria monocytogenes. (Note: never take essential oils internally!)
Historical and modern uses of juniper are too numerous to list in detail here, but hopefully this gives you an idea of its many benefits!
Is Common Juniper Toxic?
Twigs of common juniper (Juniperus communis)
I was first alerted to the possibility that common juniper is perfectly safe through the excellent article on Latifa’s Herbs website, Toxic Juniper. In it, she states:
It is worth noting that it is likely safety concerns for Savin Juniper that have been indiscriminately extrapolated to other species of juniper including Common Juniper. It is frequently noted in books and online that care should be taken when ingesting juniper due to potential kidney toxicity. However, incredibly high doses, as high as 1000 mg/kg, of the essential oil of Common Juniper were fed to rats for 28 days without causing any toxicity to the kidneys (Schilcher and Leuschner, 1997). Small doses of the essential oil were even shown to have kidney protective effects in rats (Butani et al. 2003). Further, Common Juniper was traditionally used in Bosnia and Herzegovina for kidney and urinary system disorders (Redzic, 2007). I was pleased to find that the Finnish herbalist Henriette Kress (2010) shares the same observation with regards to Common Juniper on her website.
It is possible that other species of juniper are also perfectly safe, but as most of the research focuses on common juniper (Juniperus communis), I will do so as well.
One concern often cited with common juniper is that it contains isocupressic acid, a compound found in certain conifer species that is known to cause late term abortions in cattle. Unfortunately, its effects in humans is not well understood. It is therefore recommended to avoid medicinal doses of plants containing significant amounts of this compound (such as common juniper and Ponderosa pine) during pregnancy.
Another controversial compound is thujone, which is found in many edible and medicinal plant species, both cultivated and wild. However, much of the fear around thujone has its roots in anti-absinthe pandemonium in the late 1800’s and early 1900’s. Later research proved that thujone had little to no role in the convulsions, hallucinations, and mental deterioration ascribed to absinthe. Rather, it was the high alcohol content that lead to health and social problems. Regardless, both common juniper and eastern red cedar have low traces of thujone, if any at all.
Numerous studies have reported on the non-toxicity of common juniper, including the one cited by Latifa’s Herbs above, and this research paper on therapeutic uses. Furthermore, common juniper berry oil was given GRAS (Generally Recognized as Safe) status by the Flavoring Extract Manufacturers Association in 1965 and is approved by the US Food and Drug Administration for food use. However, according to Adverse Effects of Herbal Drugs 2, “both the British Herbal Pharmacopoeia and the Kommission E. monograph produced by the … German Health Ministry indicate that juniper berries [no species given] should be avoided in renal disease. These warnings were amplified by Czygan who reported that after continued use or overdosage, kidney damage arose…. He recommended that juniper berry products should not be used without medical advice for more than 4 weeks and that these preparations were contraindicated in cases of nephritis and pyelitis.” (page 224)
So the kidney-related warnings about juniper seem to stem from the late Franz-Christian Czygan, a German pharmacist and biologist. But which species of juniper did he indicate? And under what circumstances did kidney damage arise? Unfortunately I cannot find the answers to these questions, as I cannot locate the original article from 1987, “Warnung vor unkritischem gebrauch von Wacholderbeeren” in the Zeitschrift für Phytotherapie. I speak German and did a fair deal of internet sleuthing, but can only find the publication going back to 2005. If you have any leads, I’d love to hear them!
In Summary
Unfortunately I cannot reach a complete conclusion regarding the toxicity of juniper, as there is too much contradictory information and I can’t find the paper that may unlock some of the mystery. But here is a TLDR!
Avoid toxic juniper species such as savin juniper. In Minnesota, these shrubs may be planted as ornamentals in parks or yards. Stick to varieties that are known to be safe, such as common juniper and eastern red cedar.
Common juniper is the species with the widest range of historical and modern use, and the most-researched. The use of berries and leaves of this plant are well-documented and widely considered safe.
There is some concern that common juniper can act as an abortifacient in large quantities. Therefore, only use in small amounts (or avoid altogether) if pregnant or attempting to become pregnant.
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