Chaga mushroom (Inonotus obliquus) is a type of fungus that grows mainly on the bark of birch trees in cold climates, such as Northern Europe, Siberia, Russia, Korea, Northern Canada and Alaska.
Chaga is also known by other names, such as black mass, clinker polypore, birch canker polypore, cinder conk and the sterile conk trunk rot (of birch).
Chaga produces a woody growth, or conk, which looks similar to a clump of burnt charcoal — roughly 10–15 inches (25–38 centimeters) in size. However, the inside reveals a soft core with an orange color.
For centuries, chaga has been used as a traditional medicine in Russia and other Northern European countries, mainly to boost immunity and overall health.
It has also been used to treat diabetes, certain cancers and heart disease (1).
Traditionally, chaga was grated into a fine powder and brewed as an herbal tea.
Nowadays, it’s not only available as a tea but also as a powdered or capsuled supplement. The tea may feature chaga alone or in combination with other mushrooms, such as cordyceps.
Taking chaga with either warm or cold water is believed to release its medicinal properties.
Keep in mind that reliable information on chaga’s nutritional content is extremely limited.
Inflammation is a natural response of your immune system that can protect against disease. However, long-term inflammation is linked to conditions like heart disease and rheumatoid arthritis (4Trusted Source).
Animal and test-tube studies suggest that chaga extract can positively impact immunity by reducing long-term inflammation and fighting harmful bacteria and viruses.
By promoting the formation of beneficial cytokines — specialized proteins that regulate the immune system — chaga stimulates white blood cells, which are essential for fighting off harmful bacteria or viruses (5Trusted Source, 6Trusted Source).
As a result, this mushroom could help fight infections — from minor colds to serious illnesses.
Additionally, other animal and test-tube studies demonstrate that chaga can prevent the production of harmful cytokines, which trigger inflammation and are associated with disease (5Trusted Source, 7).
For example, in a study in mice, chaga extract reduced inflammation and gut damage by inhibiting inflammatory cytokines (8Trusted Source).
Several animal and test-tube studies show that chaga can prevent and slow cancer growth (9Trusted Source).
In a study in mice with cancer, chaga supplements resulted in a 60% reduction in tumor size (10Trusted Source).
In a test-tube study, chaga extract prevented the growth of cancer in human liver cells. Similar results were observed with cancer cells of the lung, breast, prostate and colon (11Trusted Source, 12, 13Trusted Source, 14Trusted Source).
It’s thought that the anticancer effect of chaga is partly due to its high content of antioxidants, which protect cells from damage by free radicals (15Trusted Source).
Keep in mind that human studies are needed in order to make strong conclusions about chaga’s anticancer potential.
A recent study in obese, diabetic mice observed that chaga extract reduced blood sugar levels and insulin resistance compared to diabetic mice who did not receive the supplement (18Trusted Source).
In another study in diabetic mice, chaga supplements led to a 31% decrease in blood sugar levels over three weeks (17Trusted Source).
However, as human research is unavailable, it’s unclear whether chaga can help manage diabetes in humans.
Chaga extract may also benefit cholesterol levels, reducing your risk of heart disease.
Researchers believe that the antioxidants present in chaga are responsible for its effects on cholesterol.
Again, more research in humans is needed to clearly understand chaga’s cholesterol impact.