Last Updated: September 28 2022

Chaga, also known as Inonotus obliquus, is a mushroom commonly used as a dietary supplement. There are claims that it has beneficial effects on immune function and cancer prevention. However, these claims are limited to in vitro (studies done in petri dishes or test tubes) and animal studies, as there is only one study in humans.[15]

Chaga is most often used for


What is Chaga?

With its charcoal-like appearance, Chaga is a fungus that grows primarily on the trunks of birch trees. Once Chaga infects a tree trunk, it can grow there for up to 80 years. The mushroom has been used for centuries and is often touted as a cure-all within the realm of alternative medicine: from gastrointestinal diseases to cancer, there are few ailments for which Chaga has not been used as a potential remedy.[1]

What are the potential benefits of Chaga?

Chaga contains a wide variety of potentially beneficial chemical compounds, such as polyphenols, melanin, triterpenoids, and polysaccharides. Among these, polysaccharides are the most well researched.[2]

Currently, there is lab-based research that suggests Chaga may have a number of desirable effects:

Cancer: Chaga has shown anticancer properties in both in vitro and in vivo (i.e., animal-based) research, inhibiting cancer cell replication and stimulating anticancer activity in the immune system.[3][4]

Viral infections: Chaga can impair a virus’s ability to enter target cells in vitro, an effect that has been studied in feline viruses, herpes simplex, and hepatitis C.[5][6][7]

Oxidative stress & Inflammation: The polysaccharides present in Chaga can reduce markers of oxidative stress and inflammation in vitro.[8][9][10][11]

Fatigue: Chaga was able to lower fatigue in exercising mice.[12][13]

Gut Health: Chaga improved markers of gut health and the gut microbiome in mice with chronic pancreatitis.[14]

Are there any human studies using Chaga?

To date, the only study on the effects of Chaga in humans is a case series (a study that looks at a group of people receiving the same treatment) from 1973.

In this study, 50 people with both gastrointestinal disease and psoriasis either consumed Chaga orally (1 tablespoon, 3 times per day) or applied it topically (the dosage and duration were not reported). The primary outcome was the improvement in psoriasis lesions. 38 participants were considered completely cured, 8 participants showed improvement, and 4 participants showed no effect.[15]

Considering the age of the study, lack of control group, no randomization, and no standardized measurement of psoriasis disease progression, more human research is needed to determine the utility of Chaga.

Is Chaga safe?

The safety data for Chaga is limited.

The main concern is that it contains high levels of oxalate (a compound commonly found in plants that can cause kidney stones).[16] While anecdotal evidence suggests it is relatively safe, there are two case reports of oxalate-induced kidney disease (a condition that occurs due to the buildup of calcium-oxalate crystals within the kidney) after long-term consumption of Chaga.[17][18]

One case study found that a 49-year-old man with no other diseases developed end-stage renal disease after consuming Chaga daily for 5 years.[17] However, he had also consumed more than double the recommended manufacturer dose.[17] Another case study reported that a 72-year-old woman with liver cancer developed oxalate-induced kidney disease after 6 months of consuming 4–5 teaspoons of Chaga daily.[18] It is believed that the high oxalate content of Chaga — one study found there are 6.72–97.59 milligrams (mg) of oxalate per gram of Chaga[16] — caused kidney disease in these two cases.

Is Chaga a psychedelic?

No. Although Chaga is a mushroom, it doesn’t have any psychoactive compounds.[16]

Can Chaga be consumed while pregnant or breastfeeding?

Given there are few human studies using Chaga, it is difficult to determine its safety for pregnant or breastfeeding women. As such, it is not recommended to consume Chaga while pregnant or breastfeeding unless directed by a healthcare provider.

Does Chaga have any side effects?

Unfortunately, there are no human studies directly investigating the side effects of Chaga.

Does Chaga interact with any medications?

There is some lab-based evidence that Chaga may have similar mechanisms of action (the way a substance produces an effect) to blood thinners[19] and diabetic medications.[20] Therefore, it is best to consult your healthcare provider before supplementing with Chaga.

Can other supplements raise blood oxalate levels?

Supplementing with high doses of vitamin C (>1,000 mg/day) can increase the excretion of oxalates from the kidneys.[21] This could increase the risk of kidney stones or kidney disease. Several case studies have reported oxalate-induced kidney disease due to vitamin C supplementation. [22][23][24] It’s important to note that in all of these cases of kidney disease, people were supplementing with doses ranging from 480–5,000 mg, which would suggest that the dose of vitamin C needed to cause kidney disease would differ from person to person.

What else is Chaga known as?
Note that Chaga is also known as:
  • Inonotus obliquus
  • Poria obliqua
  • Polyporus obliquus
  • Fuscoporia obliqua
Chaga should not be confused with:
  • Chagas disease
Dosage information

Chaga is most commonly sold as a dried extract, ranging in dose from 500 to 1,500 mg. The range is large due to the various extraction methods used to produce the extract. This range coupled with the paucity of human studies means there are no reliable guidelines regarding the appropriate dose of Chaga to achieve a therapeutic effect.

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1.^Konrad A Szychowski, Bartosz Skóra, Tadeusz Pomianek, Jan GmińskiInonotus obliquus - from folk medicine to clinical useJ Tradit Complement Med.(2020 Aug 22)
3.^Myung-Ja Youn, Jin-Kyung Kim, Seong-Yeol Park, Yunha Kim, Channy Park, Eun Sook Kim, Kie-In Park, Hong Seob So, Raekil ParkPotential anticancer properties of the water extract of Inonotus corrected obliquus by induction of apoptosis in melanoma B16-F10 cellsJ Ethnopharmacol.(2009 Jan 21)
4.^Dong Pil Won, Jong Seok Lee, Duck Soo Kwon, Keun Eok Lee, Won Cheol Shin, Eock Kee HongImmunostimulating activity by polysaccharides isolated from fruiting body of Inonotus obliquusMol Cells.(2011 Feb)
5.^Jin Tian, Xiaoliang Hu, Dafei Liu, Hongxia Wu, Liandong QuIdentification of Inonotus obliquus polysaccharide with broad-spectrum antiviral activity against multi-feline virusesInt J Biol Macromol.(2017 Feb)
6.^Hong-Hui Pan, Xiong-Tao Yu, Ting Li, Hong-Ling Wu, Chun-Wei Jiao, Mian-Hua Cai, Xiang-Min Li, Yi-Zhen Xie, Yi Wang, Tao PengAqueous extract from a Chaga medicinal mushroom, Inonotus obliquus (higher Basidiomycetes), prevents herpes simplex virus entry through inhibition of viral-induced membrane fusionInt J Med Mushrooms.(2013)
7.^V A Shibnev, D V Mishin, T M Garaev, N P Finogenova, A G Botikov, P G DeryabinAntiviral activity of Inonotus obliquus fungus extract towards infection caused by hepatitis C virus in cell culturesBull Exp Biol Med.(2011 Sep)
8.^Haibo Mu, Amin Zhang, Wuxia Zhang, Guoting Cui, Shunchun Wang, Jinyou DuanAntioxidative properties of crude polysaccharides from Inonotus obliquusInt J Mol Sci.(2012)
10.^Ye Chan Sim, Jong Seok Lee, Sarah Lee, Youn Kyoung Son, Jung-Eun Park, Jeong Eun Song, Suk-Jin Ha, Eock Kee HongEffects of polysaccharides isolated from Inonotus obliquus against hydrogen peroxide-induced oxidative damage in RINm5F pancreatic β-cellsMol Med Rep.(2016 Nov)
11.^Trishna Debnath, Sa Ra Park, Da Hye Kim, Jeong Eun Jo, Beong Ou LimAnti-oxidant and anti-inflammatory activities of Inonotus obliquus and germinated brown rice extractsMolecules.(2013 Aug 2)
12.^Chun-Jing Zhang, Jian-You Guo, Hao Cheng, Lin Li, Ying Liu, Yan Shi, Jing Xu, Hai-Tao YuSpatial structure and anti-fatigue of polysaccharide from Inonotus obliquusInt J Biol Macromol.(2020 May 15)
13.^Zhong Yue, Zhong Xiuhong, Yang Shuyan, Zheng ZhonghuaEffect of Inonotus Obliquus Polysaccharides on physical fatigue in miceJ Tradit Chin Med.(2015 Aug)
14.^Yang Hu, Chunying Teng, Sumei Yu, Xin Wang, Jinsong Liang, Xin Bai, Liying Dong, Tao Song, Min Yu, Juanjuan QuInonotus obliquus polysaccharide regulates gut microbiota of chronic pancreatitis in miceAMB Express.(2017 Dec)
15.^E A Dosychev, V N BystrovaTreatment o psoriasis using "Chaga" fungus preparationsVestn Dermatol Venerol.(1973 May)
16.^Jasmina Glamočlija, Ana Ćirić, Miloš Nikolić, Ângela Fernandes, Lillian Barros, Ricardo C Calhelha, Isabel C F R Ferreira, Marina Soković, Leo J L D van GriensvenChemical characterization and biological activity of Chaga (Inonotus obliquus), a medicinal "mushroom"J Ethnopharmacol.(2015 Mar 13)
17.^Sua Lee, Hwa Young Lee, Yohan Park, Eun Jeong Ko, Tae Hyun Ban, Byung Ha Chung, Hyun Soon Lee, Chul Woo YangDevelopment of End Stage Renal Disease after Long-Term Ingestion of Chaga Mushroom: Case Report and Review of LiteratureJ Korean Med Sci.(2020 May 18)
18.^Yuko Kikuchi, Koichi Seta, Yayoi Ogawa, Tatsuya Takayama, Masao Nagata, Takashi Taguchi, Kensei YahataChaga mushroom-induced oxalate nephropathyClin Nephrol.(2014 Jun)
19.^D O'Shea, D PowellGrowth hormone therapy in Turner's syndromeIr Med J.(1992 Jun)
20.^You-Min Ying, Lin-Yan Zhang, Xia Zhang, Hai-Bo Bai, Dong-E Liang, Lie-Feng Ma, Wei-Guang Shan, Zha-Jun ZhanTerpenoids with alpha-glucosidase inhibitory activity from the submerged culture of Inonotus obliquusPhytochemistry.(2014 Dec)
21.^John Knight, Kumudu Madduma-Liyanage, James A Mobley, Dean G Assimos, Ross P HolmesAscorbic acid intake and oxalate synthesisUrolithiasis.(2016 Aug)
23.^Jorge Lamarche, Reji Nair, Alfredo Peguero, Craig CourvilleVitamin C-induced oxalate nephropathyInt J Nephrol.(2011)
24.^Weijie Violet Lin, Christie Gloria Turin, David Walter McCormick, Christopher Haas, Gregory ConstantineAscorbic acid-induced oxalate nephropathy: a case report and discussion of pathologic mechanismsCEN Case Rep.(2019 Feb)