Long before modern medicine, people turned to the willow tree for pain relief. Its bark contains a natural compound, the basis for aspirin, that has been used for centuries to soothe aches and pains.
Here’s how you can get the most out of this age-old remedy and learn how to make your own aspirin from willow bark.
What is Willow Bark?
Willow bark is the outer covering of several species of willow trees, most notably the white willow (Salix alba) and black willow (Salix nigra). It has a long and rich history of medicinal use, dating back thousands of years.
Ancient civilizations like the Egyptians, Greeks, and Native Americans recognized its ability to relieve pain and fever.
In the 19th century, scientists isolated the active ingredient in willow bark, salicin, which is converted to salicylic acid in the body. This discovery led to the development of aspirin, one of the world’s most widely used medications.
Where to Find Willow Bark
Willow trees are commonly found in temperate climates around the world, often growing near water sources like rivers, streams, and lakes. You can find them in North America, Europe, Asia, and parts of Africa and Australia.
If you’re looking for willow bark for personal use, you can purchase it from herbalists, health food stores, or online retailers.
Willow bark varies in color depending on the species and age of the tree. It can range from grayish-brown to reddish-brown or even nearly black. The bark is generally rough and furrowed, with deep ridges and cracks. Younger trees may have smoother bark.
How to Grow Willow Bark
While technically you don’t “grow” willow bark itself, you can cultivate willow trees, which then produce the valuable bark. Willow trees are remarkably easy to propagate and grow. Here’s how:
1. Obtaining Cuttings
- From an existing tree: In early spring, before leaves appear, take cuttings from young branches (1-2 years old) about the thickness of a pencil and 12-18 inches long.
- Purchased cuttings: Many nurseries and online retailers sell willow cuttings of various species.
2. Planting the Cuttings
- Direct planting: Simply push the cuttings about halfway into moist soil in a sunny location. Willows thrive in damp soil, so near water sources is ideal.
- Rooting in water: Place cuttings in a jar of water and change the water every few days. Once roots develop (a few weeks), transplant to soil.
3. Caring for Young Trees
- Watering: Keep the soil consistently moist, especially during the first year.
- Sunlight: Willows prefer full sun but can tolerate partial shade.
- Pruning: Prune in late winter or early spring to maintain shape and encourage healthy growth.
4. Harvesting Bark
- Sustainable harvesting: Only harvest bark from mature trees (at least three years old). Avoid stripping bark from the main trunk, as this can damage or kill the tree. Instead, take small amounts from branches.
- Time of year: The best time to harvest is in early spring before the sap starts flowing heavily.
- Method: Use a sharp knife to carefully peel away the outer bark. Leave the inner bark (cambium) intact, as this is essential for the tree’s survival.
Medicinal Uses of Willow Bark
Based on the Phytotherapy Research journal, here are some of the medicinal uses of willow bark:(ref)
- Pain Relief: A small number of clinical studies have shown that willow bark extracts can be effective in relieving chronic lower back pain and joint pain, particularly in cases of osteoarthritis. However, further research is needed to confirm these findings.
- Anti-inflammatory Effects: Both in vitro and animal studies have demonstrated the anti-inflammatory activity of willow bark extract, primarily due to its ability to downregulate inflammatory mediators like tumor necrosis factor-alpha and nuclear factor-kappa B.
- Sports Performance and Weight Loss: Although willow bark extracts are often included in products for these purposes, there are no human studies that directly support their effectiveness in these areas.
- Cancer: In another study, willow extract killed 75-80% of leukemia cells in lab tests from ALL and AML patients.(ref)
- Dysmenorrhea: A study of 96 female students with menstrual cramps showed that willow bark extract was more effective in reducing pain than mefenamic acid, a common pain reliever. Most students taking willow bark had no or mild symptoms, while those taking mefenamic acid experienced moderate symptoms.(ref)
How To Make Your Own Aspirin Using Willow Bark
Important Disclaimer: While willow bark contains salicin, the precursor to aspirin, making true aspirin at home is a complex chemical process and not recommended due to safety concerns. It’s best to purchase aspirin from a reputable source. However, you can make a willow bark extract that can provide similar pain-relieving benefits.
1. Select & Gather
Look for smaller branches on the willow tree as they tend to have the most potent bark. Focus on harvesting these.
2. Peel the Bark
Using a knife, carefully peel the bark away from the branches and larger twigs. Think of it like peeling a potato, aiming for the outer layer and the greenish inner bark, but not going too deep into the wood.
3. Separate & Discard
You’ll notice an outer layer of bark and a greenish inner layer. The greenish inner bark holds the most medicinal properties, so keep that part and discard the darker wood beneath it.
4. Cut & Measure
Use scissors to cut the bark into smaller pieces. Measure out a tablespoon of bark for each cup of tea you want to make. This makes it easier to get the right dosage.
5. Prepare the Tea
Boil two cups of water for each cup of tea you’re making. Once the water is boiling, add two tablespoons of cut willow bark. Let it boil for 10 minutes.
6. Steep & Strain
Remove the pot from heat and let the tea steep for an additional 10 minutes or longer. Then, strain out the bark using a fine-mesh sieve or cheesecloth. Your willow bark tea is ready to drink.
Alternative Methods: If tea isn’t your preference, you can dry the willow bark and grind it into a powder. This powder can be encapsulated for a pill-like experience, but getting the dosage right can be tricky.
Dosage of Willow Bark Extract
Studies generally find that willow bark extracts are considered safe when used at recommended doses (120–240 mg ref).
However, there are potential side effects, such as gastrointestinal problems and allergic reactions. People with aspirin allergies or those taking certain medications should avoid willow bark.
Always talk to your doctor or a qualified herbalist before using willow bark extract, especially if you have any medical conditions or are taking medications.
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Nancy has been a plant person from an early age. That interest blossomed into a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Nancy worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.