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Oak Tree Medicine & the Acorn

Quercus and Lithocarpus spp. 

Parts Used

Bark, leaves, acorns

Herbal Actions

Astringent, cooling, antiseptic, anti-tumor, antibiotic, anti-parasitic, and anti-inflammatory. 


Growing the Future

The acorn is the embodiment of life potential. A seed that sprouts future forests and a food that sustains its inhabitants. Acorns beckon our relationship with the natural world, and today they encourage the ‘rewilding’ of humankind. 


As a California Herbalist working with the Oak trees is essential to being in relationship with the bioregional landscape. More than half of all the species of Oak trees in North America live in California. There are approximately 600 species of Oak worldwide, 91 species of Oak in North America, 49 species in California and 14 of those species live right here in my home turf of Nevada County. Oaks are an important botanical resource used in ceremony, food, medicine and building for as long as humans have been around.

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The native peoples of California are well known for their acorn rich diets, some tribes consumed as much as half of their annual diet from acorns. This was also true of our local Nisenan tribe of the Sierra Foothills. Sometimes I envision Native ancestors of the land gathering plants and acorns at the same sites that I do today.

It is in the gathering and eating of acorns that one becomes entwined with the web of life’s basic skills: foraging, Earth-centered interaction, ancestor worship, wildlife observation, forest conservation, human health, nutrition, and ecology. Oak trees from which acorns come, teach us to be in right relationship with the natural world, rising our awareness to something greater than ourselves. The study and practice of herbs is not just about gathering an encyclopedia of remedies for the occasional illness. Herbalism is a way of life that bleeds into the art and daily practice of living. How we spend our time on this Earth, interaction with the world around us, and what we choose to eat are far more important than what herbs we take when we get sick. The acorn sits in the middle of it all, acting as a doorway between multitudes of earth centered activities. 

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Oaks are home to more species of Nature’s creatures than any other tree. They foster a spectrum of mosses, lichens, fungi, insects, birds and critters within their sturdy branches. Woodpeckers, owls, bats, deer, squirrels, mice, wrens and jays all find food and shelter from this giving tree. The Oak willingly gives water and nutrients as a home for mistletoe. Just as well, Oak’s relationship with various funguses and ectomycorrhizae plays an important role in the establishment of healthy and fertile soil, and Oak forests are an ideal place to look for delectable truffles. Holes and crevices in the tree’s bark become nesting spots for beetles and large varieties of bugs. Over 5000 species of insects find their homes within Oak ecosystems. The Oak tree is truly an entire kingdom unto itself.

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“Oaks are keystone species, meaning that the whole web of life is disproportionately dependent on them.

If the oaks suffer, everyone suffers.

If the oaks are happy, everyone is happy.”

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Acorns as a Traditional Food

Wherever there are Oaks there are acorns, and wherever there are acorns people ate them. There is prehistoric evidence of acorn eating cultures found across the globe. Acorn eating took place from China to Crimea, from the Mediterranean basin to the British Isles. 


Around the world acorns have been and still are a traditional food. If we had a table with piles representing the amount of each food consumed in human history, acorns would be the biggest pile on the table, bigger than wheat and corn combined. The Tartars of Crimea were still eating a thick-crusted, spongy acorn bread at the end of the 19th century, and to this day the remaining semi-nomadic peoples of Northern Mexico depend on the “bellota” as an important food source.   

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There is evidence that the people of Catal Huyuk, an early Neolithic settlement (circa 7500 BCE) in the Fertile Crescent region of Turkey, were grinding and storing acorns long before they were farming wheat and barley. Pliny the Elder himself (the Roman naturalist, historian and philosopher extraordinaire, as well as naval captain and army commander) wrote: “acorns at this very day constitute the wealth of many races.” Acorn eating continued to be important in the Mediterranean through the time of the Ancient Greeks. It was the food associated with the strength and intelligence of the Golden Age. 'Balanos' is Greek for acorns, and cultures who derive significant subsistence from acorns became known as "Balanocultures."

“Balanocultures were among the most stable and affluent cultures

the human world has ever known.”

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Greek necklace made of gold, with acorns & a ram's head - 5th century BC

Acorns are a traditional food for many of the indigenous peoples of North America. They serve an especially important role for Californian Native Americans, where the ranges of several species of Oaks overlap, increasing the reliability of the resource. Unlike many other plant foods, acorns do not need to be eaten or processed right away, but may be stored for a long time.

Native people of California have been eating acorns for at least 10,000 years that we know of, and many still do to this day. Like other California tribes, the Nisenan were hunters and gatherers who practiced a grooming of their gathering grounds, with fire as a primary tool for this purpose. They tended local groves of Oak trees to maximize production of acorns, which were their principal dietary staple. Oak forests were seen as wild orchards of the natural landscape. 

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Native American woman pounding and grinding shelled and skinned acorns.

Acorn-centered cultures spent several weeks a year focused entirely on the annual acorn harvest. Each community member would go out into the grove and carefully select their tree. They make camp under its branches, sleep next to its roots, and they make their evening fire there, while each day collecting its precious fruit. These gatherings in the oak grove created community festivities with ritual, music and storytelling.  Acorn ceremonies were an important part of the community encampment that took place during the gathering season. One year’s harvest can be abundant enough to feed a tribal community for up to four years.  

Today, the acorn is an untapped food source. Thousands of pounds of food are left to rot on the ground year after year, all the while there are people starving and malnourished. Many of them are simply unaware of the abundant and nutritious food laying scattered at their feet. Perhaps it is our cultural disconnection from the oaks and acorns that got us into the modern food crisis that we are in. A return to acorn eating could very well save the future of the human food supply. 


Mythology & Symbolism of the Oak Tree

In most traditions the oak is acknowledged as a sacred tree. They are known as the doorway leading between the worlds. The mighty oak grows strong and tall, and its roots grow deep into the earth giving it stability. These physical traits inspired the symbolism associated with the oak tree: strength, protection, endurance, power, triumph, wisdom and kingship. Oak trees are often referred to as the "King of the Forest," since they can reach heights over 100 feet, and average an age of 300 years. 

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The Oak King

As a symbol that is spiritually revered in many tribal cultures, oak is sometimes referred to as ‘the World Tree’. The mirrored above ground branching to below ground rooting patterns are indicative of oaks. Oaks' branching crown represents the sky, the realm of heavenly deities and celestial bodies, the trunk is the realm of mortals, and the roots of the tree the underworld.

Celtic Lore

The ancient Celts considered oaks to be the most sacred of all trees. Oak groves were used as sacred places of worship before churches came to be, and the Druids are named after this holy tree. The Celtic Ogham’s reference to oak, as ‘Duir’, is rooted from the Sanskrit word 'dwr' meaning door. A portal to the divine. Duir is a word meaning solidity, steadfastness, and protection. The Gaelic word for Oak tree 'doire' is also derived from 'duir.' The Dara Knot is a widely recognized and ancient Celtic symbol that represents the mighty Oak and it's strong root system. The design has no beginning or end. Like the Oak tree, it stands for strength, stability, power, fortitude and wisdom. 

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Dara Knot

Later in Europe, many churches were built in or by ancient Oak groves as a natural progression from ancient Oak worship. One such example is in Kildare, Ireland where St. Brigid founded her abbey. The name derived from ‘Cill-dara’, meaning the "Church of the Oak."

It is the height of midsummer that the Oak tree rules, when the Oak is in flower, marking the longest days of the year. Thus, the Oak is associated with the Summer Solstice. This is also the season of the Green Man, a symbol of the cycle of life, death and re-birth. The Green Man is often depicted in oak leaves. 

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Watch the first signs of spring, and take note for the coming rains with oak…

"If the Oak's before the Ash, 
Then you'll only get a splash; 
If the Ash before the Oak, 
Then you might expect a soak."


The Green Man

Norse mythology & the Ancient Greeks

Oaks are struck by lightning more often than any other tree of the same height. Conducting electricity is one of its influences with divine connection. This feature, being touched by the fire of heaven, makes the Oak sacred to the various gods of lightning and thunder including Thor and Zeus. 

In the Norse tradition Yule logs were made of Oak. Since Oak is such a hard, slow-burning wood, part of the Yule time tradition was to keep part of the burned log until the next winter to rekindle the yule-tide fire. Any kind of sacred fire was always kindled with Oak. The Oak tree yields the strongest of woods, and the Vikings made their famous longships from it. 

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Oak Tree on fire from a lightning strike

In Ancient Greece, the Oak was the sacred tree of Zeus. There was a renowned Hellenic oracle during the 5th century B.C.E. called Dodona. Here they would worship and commune under the oak trees, and priests were believed to be able to communicate with Zeus through the Oak tree itself. 


The ancient site of Dodona in Greece, where an Oak tree still stands

Medicinal Use

Many of the healing properties of Oak can be attributed to the highly astringent plant constituents called tannins. Tannins bind with proteins in tissues, making a barrier resistant to bacterial invasion. They also strengthen tissues and blood vessels. They reduce inflammation and irritation, especially of skin and mucus membranes. Tannins play a key role in assisting healthy microbiota. They decrease intestinal permeability and support cultivation of healthy gut flora. Oak tannins can shift gut flora imbalances to thereby successfully treat long term chronic diarrhea in a single dose. Likewise, too much tannic acid can impair the ecological balance of gastrointestinal flora. Oak bark combines well with chamomile for aiding the digestive system. Oak bark can successfully treat antibiotic resistant strains of E. coli. 

The term "tanning hides" comes from the word tannin. It involves a process which permanently alters the protein structure of the animal skin, making it durable and less susceptible to decomposition. Historically, tanning used tannins derived from the bark of certain trees, including Oak trees.

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Oak strengthens poor digestion and is excellent for controlling loose stools. Decoctions of the inner bark are used to promote healing of bleeding gums when used as a mouthwash. Finely powdered dried inner bark can be used to control nosebleeds or can be sprinkled on skin ulcers to soothe and strengthen tissues, reduce swelling and prevent infection. A decoction of the leaf used as a compress helps to soothe and shrink hemorrhoids, varicose veins and bruises or may be used as a douche to treat vaginal infections. Bark decoction can also be used as a gargle to relieve sore throats. Oak leaf poultices help clear up skin problems such as rashes, irritation and swelling. Oak has also been used historically in the treatment of cholera and gonorrhea.

"The bark of the oak is a very powerful astringent; it stops purgings, and overflowings of the menses, given in powder; a decoction of it is excellent for the falling down of the uvula, or as it is called the falling down of the palate of the mouth. Whenever a very powerful astringent is required, oak bark demands the preference over every thing: if it were brought from the East Indies, it would be held inestimable." 
- John Hill, The Family Herbal, 1812

Native American peoples use Oak to treat bleeding, tumors, swelling and dysentery. European herbalists use Oak as a diuretic and as an antidote to poison. The leaves can be employed to promote wound healing. Oak can also be used as a Quinine substitute in the treatment of fevers. Leaves may be used fresh for first aid in the field. They can be softened by immersing them in boiling water or steaming until limp. If boiling water is not available, the leaves may be softened by crushing them. Apply the leaves topically to the affected area as an antiseptic, soothing poultice to reduce swelling, skin irritation or bleeding.

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Preparation & Dosage

Every part of the Oak tree has an important use, whether it’s for food, medicine, prayer or shelter. The parts of the plant that can be used for medicine include the inner bark, twigs, leaves, and galls.

Dried Leaves, Stems and Bark

Tincture 1:5, 50% etoh, 10% glycerin. Strong Decoction or Cold Infusion with dose ranges from 1 to 4 ounces up to four times a day, or applied topically as needed. 

Fresh leaves

May be gathered for first aid as needed, and made into poultices.


The bark is higher in tannins than the leaves and much more astringent when harvested in the Spring. The ideal time to collect oak bark is before the trees flower at midsummer. Some say between March and June, others say between May and July. The differences will vary on the region and species of Oak.  

Galls or oak apples

Oak apple or oak galls are the common names for the large, round, vaguely apple-like gall commonly found on many species of Oak. These oak apples range in size from 2 to 4 cm (1 to 2 in) in diameter and are produced upon the oak, not as fruit, but from the wounds made by an insect, typically moths. Fresh tincture 1:2 or dried galls same as leaves and bark, diluted for topical use; powdered galls can be mixed with a little hot water for topical use as a poultice. 


Gathered in the fall and are an excellent nutrient dense food source. Acorns are not produced until the tree is at least 40 years old. Peak acorn production usually occurs around 80 – 120 years, and some trees can live longer than 500 years. One large oak tree can produce 1,000 pounds of acorns in a year. There is lots of variation among Quercus and Lithocarpus species members. Some are much richer in tannins, while others are a bit milder in their astringency. Acorn foragers find astringency levels among species groups to vary greatly. Acorns are a nutrient dense food. They are lower in fat and sugars then many other nuts. Acorns provide about 125 calories per ounce. They are rich in polyunsaturated fats, vitamin B6, copper, manganese, phosphorous and potassium. Raw acorns contain a high amount of tannins. Tannins are phytochemicals that have a bitter taste and are typically extracted by the leeching process that turns acorns into food. While we prefer to avoid large consumption of tannins in our food, tannins have an astringent property which have significant medicinal uses. There are many methods for leeching and processing acorns into food. In fact there are so many ways to approach acorn eating that entire books have been written on the subject.

Flower Essence

Oak is a part of the original 38 flower remedies created by Dr. Edward Bach. It is used for those with feelings of despondency and despair. Those who hopelessly struggle to get on with daily life, despite their nature to fight on. When such cases of chronic illness interferes with the ability to perform basic duties or help others oak essence can help to shift the paradigm. It grants the ability to endure and carry on during tough times. 


Frequent consumption of any high tannin containing herbs can lead to gastric irritation and put stress on the kidneys. Do not use Oak for people who suffer from constipation. Oak is not recommended for large open wounds or for treatment of weeping eczema.


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