Mushrooms · Wild culinary mushroom
Birch bolete
Leccinum scabrum · also called Brown birch bolete, rough-stemmed bolete
Birch bolete is a wild mushroom that people eat cooked. It is a food, and we found no human trial showing a health benefit from eating it. Reviews say it must be cooked thoroughly, because some Leccinum can upset the stomach and bowel if not cooked properly. Wild mushrooms can also carry metals and radioactive caesium from the soil.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Birch bolete
Birch bolete is a wild edible mushroom, eaten cooked. Its research is mostly about what is in it, not what it does for health, and we found no human health trial. The cautions are practical: cook it thoroughly, never eat a wild mushroom unless an expert has identified it, and know that wild mushrooms can carry cadmium and radioactive caesium that depend on where they grew.
What it is
Birch bolete is a fungus, Leccinum scabrum, in the family Boletaceae. GBIF lists the name as accepted and Boletus scaber as an older synonym. It is also called brown birch bolete or rough-stemmed bolete. The 2026 genus review says Leccinum fungi live in partnership with the roots of many trees, so the mushroom is collected wild.
Food use and traditional use
The genus review says Leccinum species are among the most widely collected and eaten wild mushrooms in cool northern regions. We found no traditional medicine use in the sources we read, so none is claimed.
What the research shows
A 2025 paper reported vitamins, minerals, protein and fibre in one dried sample from a forest on the Poland-Belarus border, and found that water extracts slowed bacteria in lab dishes. A Polish study of three boletes found dried birch bolete scored highest on two antioxidant tests. A 2024 paper found a solvent extract blocked sugar-digesting enzymes in test tubes, with a preliminary test in fruit flies. All of this is chemistry or lab work. We found no human trial of birch bolete for any health outcome; our search was not exhaustive.
Metals and radioactive caesium
In dried birch bolete from two regions of north-western Poland, mean cadmium was 1.12 mg per kg, with 0.31 in one region and 1.93 in the other. Mean lead was 1.55 and nickel 3.18 mg per kg. The authors say all metals were within EU food limits. They warn that regular or excessive eating of porcini may exceed tolerable weekly intakes for cadmium and nickel, but they do not say this of birch bolete. Dried mushroom is concentrated, so always check whether a figure is per fresh or per dried weight.
In a Baltic-coast study near Gdansk, whole fresh birch bolete held 2.0 Bq per kg wet weight of caesium-137, against 9.0 for porcini, and the projected dose from a 100 g portion was low. In the same lab study, across three bolete species, blanching cut caesium-137 by 15 percent and blanching with vinegar pickling by 55 percent. The genus review says caesium-137 is still raised in parts of Ukraine and Eastern Europe. This is a research finding, not cooking advice.
At a glance
Traditional uses history, not proof
- Eaten as a wild mushroom, widely collected in cool northern regions (2026 genus review).
- No traditional medicine use was found in the sources we read.
Studied for research
- Nutrition as a food, insufficient evidence of any health effect
- Antioxidant chemistry in extracts, insufficient (test-tube results only)
- Blood-sugar enzyme blocking and antibacterial activity, insufficient (test tubes and insects only)
- Immune, anti-tumour and serotonin-related ideas, insufficient (review statements, no human trial)
Main compounds
- Phenolic compounds such as catechin, and quinic acid
- Beta-glucans and other polysaccharides
- 5-hydroxytryptophan and serotonin (reported in a review)
- Cadmium, lead, nickel and radioactive caesium taken up from the soil
Common forms
- Fresh, thoroughly cooked mushroom
- Dried mushroom, soaked before cooking
- Pickled (tested for caesium in one study)
- Powders, extracts and capsules (not assessed in the sources we read)
Research links: Penn State Extension: Preparing and preserving mushrooms · The genus Leccinum: a 2026 review (abstract) · Boletes compared: metals and antioxidants (abstract) · Caesium-137 and home processing of boletes (abstract) · Birch bolete composition and antibacterial study (abstract) · Blood-sugar enzyme study in the lab (abstract) · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Leccinum scabrum
- Naming authority
- (Bull.) Gray (GBIF)
- Synonyms
- Boletus scaber (GBIF lists it as a synonym of Leccinum scabrum)
- Common names
- Birch bolete (English); Brown birch bolete (English); Rough-stemmed bolete (English); Birken-Röhrling / Gemeiner Birkenpilz (German); Koźlarz babka (Polish)
- Family or group
- Boletaceae (a fungus family; boletes), not a plant
- Classification
- Fungi > Basidiomycota > Agaricomycetes > Boletales > Boletaceae > Leccinum > Leccinum scabrum
- Native range
- The genus review says Leccinum is widespread across boreal, temperate, Mediterranean and some tropical regions. Where birch bolete grows was not checked beyond that.
- Habitat
- The genus review says Leccinum forms ectomycorrhizal partnerships with over 60 woody host genera: the fungus lives on tree roots and forms the mushroom above ground.
- What it looks like
- Fruiting body: Not described here. Identification of wild mushrooms must be done in person by an expert, so no field description is given.
- Cultivation
- Wild-collected in the sources read; no cultivation source was read.
- Harvest and processing
- Eaten cooked; sold fresh or dried and soaked. Blanching and vinegar pickling were tested for caesium (see Safety). Details not checked.
- Look-alikes and adulterants
- Name: Other Leccinum species; Note: The genus review says some guides do not recommend certain types, such as orange-capped Leccinum, because of potential toxicity. No source we read names species that look like birch bolete.
- Sustainability and conservation
- Not checked.
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Food use | The genus review calls Leccinum species among the most widely collected and consumed wild mushrooms in boreal and temperate regions. No traditional medicine history was found in the sources read, so none is stated. | p41590482 |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Phenolic compounds (catechin, quercetin, gallic acid) and quinic acid | phenolic compounds | Fruiting body Not stated in the abstract. | Linked to antioxidant test scores in extracts. 7 | Laboratory research |
| Beta-glucans and other structural polysaccharides | polysaccharide | Fruiting body Boletus edulis had the highest beta-glucan of the three boletes; the birch bolete value was not re-opened. | Composition fact. 7 | Compositional analysis |
| 5-hydroxytryptophan and serotonin | indole compounds | Fruiting body Not given. | Reported in the genus review; effect of eating them was not shown. 1 | Expert opinion |
| Cadmium, lead, nickel, mercury (contaminants) | metals | Fruiting body Mean cadmium 1.12, lead 1.55, nickel 3.18 mg per kg in dried samples from two Polish regions. | Contaminants taken up from the soil. 7 1 | Compositional analysis |
| Caesium-137 (contaminant) | radionuclide | Whole fruiting body 2.0 Bq per kg wet weight in whole fresh birch bolete near Gdansk. | Contaminant from old fallout. 2 | Compositional analysis |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Sugar-digesting enzymes (alpha-glucosidase, alpha-amylase) | not specified | An ethyl acetate extract blocked both enzymes in test tubes, alpha-glucosidase much more strongly; a preliminary fruit-fly test agreed. No human finding. 3 | Laboratory research |
| Antioxidant tests (ABTS, FRAP) | not specified | Highest scores of three boletes in the tests, linked to phenolic compounds. Test-tube chemistry only. 7 | Laboratory research |
| Bacterial growth | not specified | Aqueous extracts slowed all bacteria tested in dishes. 5 | Laboratory research |
Absorption, metabolism and elimination
- Absorption
- Not found for birch bolete.
- Distribution
- Not found.
- Metabolism
- Not found.
- Elimination
- Not found.
- Bioavailability
- Not established.
Isolated compounds versus whole extracts
Birch bolete is eaten as a cooked whole food. The lab results here come from solvent or water extracts, which are not the same as the cooked mushroom. No powder, extract or capsule was assessed.
Nutritional composition
The 2025 composition paper reports vitamins, minerals, protein, fibre and carbohydrates in one dried sample (no figures in its abstract). USDA has no birch bolete entry in the files we hold, so no nutrient table is given. A Baltic-coast study projected about 330 mg potassium in a 100 g portion of blanched or pickled bolete (several species pooled).
6 not enough evidence
What was looked at
The 6 benefits and uses checked for Birch bolete, each with how strong the evidence is. Tap one to open it.
- Nutrition as a foodNot enough evidence
- Antioxidant chemistry (test-tube results)Not enough evidence
- Blood-sugar enzyme blocking (test tube and insects)Not enough evidence
- Antibacterial activity in dishesNot enough evidence
- Serotonin-related compounds (a hypothesis)Not enough evidence
- Immune and anti-tumour activity reported for the genusNot enough evidence
What is Birch bolete good for?
The uses people ask about and how strong the human evidence is for each. None is proven for birch bolete. Read this together with the Safety tab.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Nutrition as a food
Not enough evidenceBirch bolete is a wild culinary mushroom. One dried sample from a Polish-Belarusian forest was reported to hold vitamins, minerals, protein, fibre and carbohydrates. This describes what is in it. No trial shows a health benefit from eating it.
2 studiesEaten cooked. Dried mushroom is concentrated (drying removes water), …
Studies, doses and limits
What the trials found
No human trial of eating birch bolete was found.
Results
The abstract of the 2025 composition paper gives no figures. The full-text figures were not re-checked here, because they came from a single dried sample, and the paper has a published erratum we did not read. USDA has no birch bolete entry in the files we hold, so no nutrient table is given.
Why this rating
Composition data from one dried sample and general reviews; no study measured a health effect of eating it.
Form and dose studied
Eaten cooked. Dried mushroom is concentrated (drying removes water), so figures per gram of dried and fresh mushroom are not comparable.
Who was studied
General food use
Limits
One sample, one forest. Wild samples differ by place and age.
Why researchers looked
It is mainly a food, so most research measures what is in it rather than what it does in people.
Traditional use
No traditional medicine use was found in the sources we read.
Proposed mechanism Compositional analysis
Not applicable: this is a composition fact, not a mechanism.
A proposed mechanism does not show that the effect happens in people.
Wild birch bolete can also carry metals and radioactive caesium, and must be cooked; see the Safety tab.
Antioxidant chemistry (test-tube results)
Not enough evidenceIn a Polish study of three boletes, dried birch bolete scored highest on two antioxidant tests (ABTS and FRAP). It held phenolic compounds such as catechin. These are test-tube measurements on extracts. They do not show an antioxidant benefit from eating the mushroom.
2 studiesDried, ground mushroom extracts in the lab; not a food or supplement.
Studies, doses and limits
Results
Highest ABTS and FRAP of three boletes; the DPPH test was highest in another species (Imleria badia). No human result.
Why this rating
Lab chemistry only; no study in people or animals of eating birch bolete.
Form and dose studied
Dried, ground mushroom extracts in the lab; not a food or supplement.
Limits
Two regions of north-western Poland, one season; test-tube scores do not predict effects in the body.
Why researchers looked
Mushrooms and their phenolic compounds are often tested for antioxidant activity in the lab.
Proposed mechanism Laboratory research
Phenolic acids and catechin were correlated with antioxidant test scores in the paper. This is chemistry in extracts, not a finding in people.
A proposed mechanism does not show that the effect happens in people.
None specific. Cadmium, lead and nickel were measured in the same samples; see the Safety tab.
Blood-sugar enzyme blocking (test tube and insects)
Not enough evidenceA solvent extract of birch bolete blocked two sugar-digesting enzymes in test tubes, and a preliminary test in fruit flies agreed. No study in people was found. This does not show that eating birch bolete lowers blood sugar.
1 studiesA solvent extract made in the lab, not a food.
Studies, doses and limits
Results
The ethyl acetate extract blocked alpha-glucosidase with an IC50 of 0.42 microgram per mL, about 60-fold lower than the reference compound; amylase blocking was milder.
Why this rating
Test tube and insect evidence only, from the abstract.
Form and dose studied
A solvent extract made in the lab, not a food.
Limits
Abstract only; a solvent extract does not predict what happens when the mushroom is eaten.
Why researchers looked
Blocking alpha-glucosidase and alpha-amylase is one way some diabetes drugs work, so researchers screen foods for it.
Proposed mechanism Laboratory research
Enzyme inhibition by an ethyl acetate extract in vitro; a preliminary fruit-fly test.
A proposed mechanism does not show that the effect happens in people.
People with diabetes should not rely on any mushroom; ask a clinician.
Antibacterial activity in dishes
Not enough evidenceHot-water extracts of dried birch bolete slowed the growth of several bacteria in lab dishes. It is not an antibiotic and was not tested in people.
1 studiesLab extracts, not a food.
Studies, doses and limits
Results
All tested bacteria were slowed by the aqueous extracts; the microwave extract was strongest against Listeria monocytogenes (ATCC 19114). No figures in the abstract.
Why this rating
Dish-level evidence only, from the abstract.
Form and dose studied
Lab extracts, not a food.
Limits
One dried sample from one forest; abstract only; an erratum exists.
Why researchers looked
Mushroom extracts are screened for antimicrobial activity.
Proposed mechanism Laboratory research
Extracts inhibited growth of tested bacteria in vitro; the abstract does not name the compounds responsible.
A proposed mechanism does not show that the effect happens in people.
None.
Serotonin-related compounds (a hypothesis)
Not enough evidenceA 2026 review says birch bolete contains 5-hydroxytryptophan and serotonin and suggests it could be a helpful dietary item for low mood. This is a guess based on what is in the mushroom. No trial was found, and we could not open the source behind it.
1 studiesNot assessed.
Studies, doses and limits
Results
No result; composition statement and hypothesis only.
Why this rating
A statement in a review whose underlying source we could not verify.
Form and dose studied
Not assessed.
Limits
Hypothesis only; presence of a compound does not show an effect.
Why researchers looked
The compounds are related to the body's own serotonin, so a possible link to mood is raised in the review.
Proposed mechanism Expert opinion
Presence of precursors in the mushroom. Whether they reach the brain after eating was not shown.
A proposed mechanism does not show that the effect happens in people.
Do not use any wild mushroom to treat low mood; talk to a clinician if you have symptoms.
Immune and anti-tumour activity reported for the genus
Not enough evidenceThe 2026 genus review lists immunomodulatory and antitumour activities for Leccinum species. These are described as laboratory findings in the review. We could not check the studies behind them, and no human trial of birch bolete was found.
1 studiesNot assessed.
Studies, doses and limits
Results
No result stated; the review's abstract lists the activities without figures.
Why this rating
Statement in a narrative review, not verified at the source.
Form and dose studied
Not assessed.
Limits
Applies to the genus; some of it may not be about Leccinum scabrum.
Why researchers looked
Mushroom polysaccharides are widely tested in the lab for immune effects.
Proposed mechanism Laboratory research
Lab findings for polysaccharides and other compounds, per the review. The specific studies were not opened.
A proposed mechanism does not show that the effect happens in people.
Not a treatment for any condition.
Connections to the rest of health
How Birch bolete connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Mushroom poisoning | Adverse effect or risk | Low certainty | Genus review and extension guidance. Preparation or compound: Undercooked or misidentified wild mushrooms |
1 6 |
G. Root causes and contributing factors
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Heavy metal exposure | Moderate certainty | Cadmium, lead and nickel; cadmium six-fold different between two regions. Preparation or compound: Wild and dried birch bolete |
7 1 | |
| Environmental toxins | Moderate certainty | Caesium-137 depends strongly on region. Preparation or compound: Wild birch bolete (radiocaesium) |
2 1 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Phenolic compounds (catechin, quercetin, gallic acid) and quinic acid | Biological association | In vitro | Linked to antioxidant test scores in extracts. Preparation or compound: Fruiting body |
7 |
| Beta-glucans and other structural polysaccharides | Biological association | Compositional analysis | Composition fact. Preparation or compound: Fruiting body |
7 |
| 5-hydroxytryptophan and serotonin | Biological association | Expert opinion | Reported in the genus review; effect of eating them was not shown. Preparation or compound: Fruiting body |
1 |
| Cadmium, lead, nickel, mercury (contaminants) | Biological association | Compositional analysis | Contaminants taken up from the soil. Preparation or compound: Fruiting body |
7 1 |
| Caesium-137 (contaminant) | Biological association | Compositional analysis | Contaminant from old fallout. Preparation or compound: Whole fruiting body |
2 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
Evidence at a glance: what the research found for 6 outcomes
Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.
The evidence
The research centre for Birch bolete. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We read PubMed records for five papers: abstracts for all five (one genus review whose full text we also read, one Polish three-bolete survey whose tables we also read, one caesium processing study whose full text we also read, one composition and antibacterial paper, one lab enzyme paper). We also read the Penn State Extension guidance page in full and checked the name in GBIF. Index Fungorum, EFSA, FDA and poison-centre statements were not read, and the genus review's own sources on poisoning were not opened. Certainty ratings are the compiler's own reading.
Study library: every study we checked 7
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Budau 2026 The Genus Leccinum: Global Advances in Taxonomy, Ecology, Nutritional Value, and Environmental Significance. Journal of Fungi · PMID 41590482 · DOI |
Narrative review mixed |
Review of 293 publications on the genus Leccinum | Leccinum species, mostly lab and composition studies fruiting body Not shown here |
The abstract says Leccinum species are rich in proteins, carbohydrates, minerals, polysaccharides, phenolic compounds and umami-related peptides, with antioxidant, immunomodulatory and antitumour activities reported, and that the genus accumulates heavy metals (mainly mercury, cadmium, lead) and radionuclides. In the full text we read: some Leccinum can cause stomach and bowel upset if not cooked properly, there are reports of poisonings, the general advice is to cook thoroughly, and some guides advise against certain types such as orange-capped Leccinum. It reports caesium-137 still raised in parts of Ukraine and Eastern Europe, and says Leccinum scabrum contains 5-hydroxytryptophan and serotonin, and suggests a possible dietary role in depression (a hypothesis). No health-outcome result Methods, limits and fundingOutcomes: Taxonomy, ecology, composition, bioactivity, metals and radionuclides Limitations: Narrative review. The sources behind its poisoning, caesium and serotonin statements (its references 130, 132, 133, 137, 138) were not opened, so these are cited to the review only. Abstract and full text read. Funding and conflicts: Authors report no conflict of interest Read: abstract and full text |
| Falandysz 2022 Effect of drying, blanching, pickling and maceration on the fate of (40)K, total K and (137)Cs in bolete mushrooms and dietary intake. Environmental Science and Pollution Research · PMID 34338984 · DOI |
Laboratory study lab |
Boletus edulis, Leccinum scabrum and Leccinum versipelle from the southern Baltic coast near Gdansk (2015) | Fresh bolete flesh, blanched, blanched and pickled in vinegar, or macerated from dried powder fruiting body Not shown here |
Relative to fresh mushrooms, blanching cut caesium-137 by 15 percent (plus or minus 13), and blanching with vinegar pickling cut it by 55 percent (plus or minus 8). Maceration of dried powder cut it by 38 percent (plus or minus 11). The authors say home processing may not remove caesium-137 as well as some earlier studies showed. A 100 g portion was projected at 0.51 to 12 Bq per kg wet weight, with an effective dose of 0.001 to 0.010 microsieverts. In the full text, whole fresh Leccinum scabrum held 2.0 Bq per kg wet weight (20 dry weight) and Boletus edulis 9.0 (90 dry weight). Caesium-137 lower after pickling; low projected dose Methods, limits and fundingOutcomes: Caesium-137 and potassium-40 before and after processing; dietary intake estimate Limitations: Results are pooled across three species in the abstract; one coastal region and year; a laboratory processing test, not cooking advice. Abstract and full text read. Funding and conflicts: Authors report no conflict of interest Read: abstract and full text |
| Ferraro 2024 Hypoglycemic Properties of Leccinum scabrum Extracts-An In Vitro Study on alpha-Glucosidase and alpha-Amylase Inhibition and Metabolic Profile Determination. Journal of Fungi · PMID 39452670 · DOI |
In vitro and insect lab |
Not stated Test-tube enzyme tests and a preliminary test in fruit flies (Drosophila melanogaster) |
Leccinum scabrum extracts made by microwave with green solvents; the ethyl acetate extract was most active fruiting body Not shown here |
The ethyl acetate extract blocked alpha-glucosidase with an IC50 of 0.42 (plus or minus 0.02) microgram per mL, about 60-fold lower than the reference compound 1-deoxynojirimycin (25.4 plus or minus 0.6). Blocking of pancreatic alpha-amylase was milder. Preliminary tests in fruit flies were said to confirm the activity. Enzyme blocking in test tubes and insects Methods, limits and fundingOutcomes: Inhibition of alpha-glucosidase and alpha-amylase Limitations: Laboratory and insect only; a solvent extract, not a food. No human data. Abstract only was read. Funding and conflicts: Authors report no conflict of interest Read: abstract |
| GBIF 2026 GBIF Backbone Taxonomy: Leccinum scabrum (Bull.) Gray (usage key 9141390), checked 2026-10-25 GBIF API · Source |
Taxonomy record n/a |
n/a | n/a Not shown here |
GBIF lists Leccinum scabrum (Bull.) Gray as ACCEPTED, family Boletaceae, order Boletales. A name search lists Boletus scaber as a synonym of Leccinum scabrum. Methods, limits and fundingOutcomes: Accepted name and synonyms Limitations: One database; Index Fungorum was not checked. Funding and conflicts: Public database Read: record |
| Gargano 2025 Nutritional contents and antimicrobial activity of the culinary-medicinal mushroom Leccinum scabrum. Mycology · PMID 40083412 · DOI |
Laboratory composition and in vitro lab |
One dried sample for composition (replicates not stated in the abstract) Wild Leccinum scabrum collected in the Bialowieza Primeval Forest (Poland/Belarus) in summer |
Dried Leccinum scabrum fruiting body; aqueous extracts made with microwave or ultrasound fruiting body Not shown here |
The abstract says the dried sample had a significant content of vitamins and minerals and a remarkable content of carbohydrates, protein, dietary fibre, total sugars, free amino acids and polyunsaturated fatty acids. Aqueous extracts slowed all the bacteria tested in dishes; the microwave extract was strongest against Listeria monocytogenes (ATCC 19114). The abstract gives no figures. Composition and lab antibacterial activity only Methods, limits and fundingOutcomes: Composition; growth of bacteria in dishes Limitations: One dried sample from one forest; extracts tested in dishes, not in people. An erratum was published (Mycology 2025;16:iii) and was not read. Abstract only was read. Funding and conflicts: Authors report no conflict of interest Read: abstract |
| Penn State Extension 2024 Penn State Extension: Preparing and Preserving Mushrooms extension.psu.edu · Source |
Authoritative guidance n/a |
n/a | n/a Not shown here |
Page text read on 2026-10-25. It says only an expert can tell poisonous from edible mushrooms, that you should not forage your own unless you are an expert, and that no matter how much you cook or dry mushrooms you will not destroy their toxins. The page shows 'Updated: November 22, 2024'. Methods, limits and fundingOutcomes: Safety statements about wild mushrooms Limitations: University extension guidance, not a regulator statement; not specific to birch bolete. Funding and conflicts: Public university Read: full text |
| Sotek 2025 Bioactive Compounds and Antioxidant Activity of Boletus edulis, Imleria badia, Leccinum scabrum in the Context of Environmental Conditions and Heavy Metals Bioaccumulation. Molecules · PMID 40807452 · DOI |
Laboratory survey lab |
Wild boletes from two forested regions of north-western Poland | Dried, ground Leccinum scabrum fruiting bodies (and two other boletes for comparison) fruiting body Not shown here |
Leccinum scabrum showed the highest ABTS and FRAP antioxidant capacities of the three boletes and accumulated quinic acid and catechin. Boletus edulis had the highest beta-glucan and the greatest cadmium. In the tables we read, mean cadmium in Leccinum scabrum was 1.12 mg per kg (0.31 in one region, 1.93 in the other; Boletus edulis 2.74, Imleria badia 0.43), lead 1.55 and nickel 3.18 mg per kg. The authors say all metals were within EU food limits, and that regular or excessive eating of Boletus edulis may exceed tolerable weekly intakes for cadmium and nickel (they do not say this of Leccinum scabrum). Cadmium about six-fold different between two regions Methods, limits and fundingOutcomes: Glucans, phenolic and organic acids, antioxidant tests, cadmium, lead and nickel Limitations: Two regions, one season; antioxidant results are test-tube measurements on extracts. Metal figures are read from the paper's tables (mg per kg dry mass as we read them). Abstract and tables read; the quinic acid mean was inconsistent in the paper and is not used. Funding and conflicts: Authors report no conflict of interest Read: abstract and full text tables |
What we do not know yet
- No human trial of birch bolete for any health outcome was found.
- No source naming poisonous look-alikes of birch bolete was read, and the review's sources on Leccinum poisoning were not opened.
- No regulatory limits for metals or radiocaesium in mushrooms were read.
- No data on allergy rates, pregnancy or breastfeeding, and no test of powders, extracts or capsules.
- Survey figures are for particular places and years and may not match any mushroom you collect or buy.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue. A person reads each one before it changes any evidence rating or safety wording. New publications never change ratings automatically.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 4
- Cook it thoroughly: Leccinum can upset the stomach if not cooked properly. A 2026 review of the genus Leccinum says some species can cause stomach and bowel problems if they are not cooked properly, that there are reports of Leccinum poisonings, and that the general advice is to cook the mushroom thoroughly. It adds that some guides advise against certain types, such as orange-capped Leccinum, because of possible toxicity. The review's own sources for these statements were not opened. Do not eat birch bolete raw. Narrative review 1
- A wrong mushroom is not made safe by cooking or drying. Penn State Extension says only an expert can tell poisonous from edible mushrooms, that you should not forage your own unless you are an expert, and that no amount of cooking or drying destroys their toxins. Never pick and eat a wild mushroom on the strength of a web page or an app. We read no source naming poisonous look-alikes of birch bolete specifically, so none is named here. Authoritative guidance 6
- Wild birch bolete takes up cadmium, other metals and radioactive caesium. In dried birch bolete from two regions of north-western Poland, mean cadmium was 1.12 mg per kg, six-fold different between the two regions (0.31 and 1.93), with lead 1.55 and nickel 3.18 mg per kg. The authors say all metals were within EU limits. The genus review says Leccinum species accumulate mercury, cadmium and lead and radionuclides. Where it grew matters most. Laboratory survey 7 1
- Radiocaesium depends on place. On the southern Baltic coast near Gdansk (2015), whole fresh birch bolete held 2.0 Bq per kg wet weight of caesium-137, against 9.0 for porcini in the same study, and the projected dose from a 100 g portion was low. The genus review says caesium-137 is still raised in parts of Ukraine and Eastern Europe decades after Chernobyl. One coast says little about another forest. Laboratory survey 2 1
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Stomach and bowel upset if not cooked properly (Leccinum in general) Statement from a genus review whose underlying sources (an incident report and a paper on mushroom identification) were not opened. It does not give figures for birch bolete itself. | Not found | not stated in the review not stated | Narrative review 1 |
| Poisoning from a wrongly identified wild mushroom General guidance, not specific to birch bolete. | Not found | can be serious unknown | Authoritative guidance 6 |
| Allergy to mushrooms No birch bolete allergy report was found in the sources read; mushroom allergy exists in general. | Not found | unknown unknown | None found |
Liver
No liver injury from eating birch bolete was found in the sources read. This is absence of evidence, not proof of safety.
Monitoring. Seek medical care for poisoning signs; no routine monitoring is suggested by the sources read.
This is a safety connection. It is not evidence that Birch bolete supports liver health.
Medicines and supplements 2
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Prescription and over-the-counter medicines prescription | No interaction report for birch bolete was found in the sources read. This is absence of evidence, not proof of safety. | None found Not enough evidence | Ask a pharmacist if you take regular medicines and plan to eat wild mushrooms often. | |
| Diabetes medicines prescription | A lab extract blocked sugar-digesting enzymes in test tubes (theory only). | Theoretical only. No human data on food or extract. | Theoretical Not enough evidence 3 | Ask a clinician; do not use mushroom extracts in place of diabetes treatment. |
Who should check first 4
| Situation | Advice | Evidence |
|---|---|---|
| Anyone who cannot be sure of the mushroom's identity | Do not eat it. Only an expert can separate poisonous from edible mushrooms, and cooking or drying does not destroy toxins (Penn State Extension). | Authoritative guidance 6 |
| Eating it raw or undercooked | Do not. The genus review says some Leccinum can upset the stomach and bowel if not cooked properly. | Narrative review 1 |
| Pregnancy, breastfeeding and young children | No birch bolete safety data were found for these groups. Because wild mushrooms can carry metals and caesium, ask a clinician before eating them regularly. | None found 7 |
| Known mushroom allergy | Ask an allergy specialist before eating or handling mushrooms. | None found |
Overdose, product quality and regulators
Summary. Birch bolete is an edible wild mushroom. The hazards found in the sources read are poor cooking, mistaken identity of wild mushrooms, and metals and radiocaesium taken up from the soil. No toxin of birch bolete itself was identified.
Animal. Not reviewed. A fruit-fly test of an extract was about blood-sugar enzymes, not toxicity.
Human doses studied. No dose studies. No amounts are advised here.
High dose or long term signals. Metal and caesium intake would add up with frequent large servings of contaminated mushrooms. The Polish authors warn about weekly cadmium and nickel intake for Boletus edulis, not for birch bolete, whose metals were within EU limits in that study.
Genotoxicity. Not read.
Toxic or hazardous parts. Fungus: cap and stem are eaten. Metals in caps versus stems were not checked.
Birch bolete is wild-collected, so what it carries depends on the soil, the region and the year. Dried mushroom is concentrated, so a figure per kg of dried mushroom is far higher than one per kg of fresh. Always check which basis a number uses.
Cadmium, lead and nickel in dried birch bolete. Two regions of north-western Poland: mean cadmium 1.12 mg per kg (0.31 and 1.93 in the two regions), lead 1.55, nickel 3.18. Boletus edulis had higher cadmium (2.74) and Imleria badia lower (0.43). The authors say all values were within EU limits. 7
Mercury and other metals. The genus review says Leccinum accumulates mercury, cadmium and lead, and that Leccinum scabrum in south-west Poland showed clear accumulation of several metals including mercury and cadmium. No mercury figure was read for birch bolete. 1
Radioactive caesium and home processing. Whole fresh birch bolete held 2.0 Bq per kg wet weight (20 dry weight) in the Gdansk-coast study. Across three bolete species, blanching cut caesium-137 by 15 percent, blanching plus vinegar pickling by 55 percent and maceration of dried powder by 38 percent. The authors say home processing may be less effective than earlier studies showed. This is a lab finding, not cooking advice. 2
Parts of Ukraine and Eastern Europe. The genus review says birch bolete and related species still accumulate raised caesium-137 there. The sources behind this were not opened. 1
| Body | Action | Date |
|---|---|---|
| Penn State Extension (United States (university)) | Says only an expert can tell poisonous from edible mushrooms, not to forage unless an expert, and that cooking or drying does not destroy toxins. source | 2024-11-22 |
When to get medical help
- Severe or repeated vomiting, diarrhoea or belly pain, dizziness, confusion or heavy sweating after eating a wild mushroom: get emergency medical help or call your local poison service now. Do not wait for it to pass.
- Unusual bleeding, passing very little urine, yellow skin or eyes, or dark urine after eating wild mushrooms: get medical help now.
- Wheezing, chest tightness, swelling of the lips or face, or hives after handling or eating mushrooms: treat as an emergency.
If someone may be poisoned or in a crisis, contact a clinician or emergency service straight away. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is birch bolete?
Is birch bolete healthy?
Does birch bolete have medicinal benefits?
Can you eat birch bolete raw?
No. A 2026 genus review says some Leccinum can upset the stomach and bowel if not cooked properly, and that thorough cooking is the general advice.
Can birch bolete poison you?
What mushrooms look like birch bolete?
We read no source that names look-alikes of birch bolete, and we do not give identification tips. Only an expert, in person, can identify a wild mushroom, and cooking or drying does not destroy toxins (Penn State Extension).
Does birch bolete contain heavy metals?
Is birch bolete radioactive?
Does pickling or blanching remove radiocaesium?
In one lab study of three bolete species, blanching cut caesium-137 by 15 percent and blanching with vinegar pickling by 55 percent, and the authors say home processing may be less effective than thought. We found no study showing it removes metals. This is a research finding, not advice.
Is dried birch bolete different from fresh?
Is birch bolete safe in pregnancy, breastfeeding or for children?
No birch bolete safety data were found for these groups. Ask a clinician before eating wild mushrooms regularly, since they can carry metals and caesium.
Does birch bolete interact with medicines?
No interaction report was found in the sources we read, which is not proof of safety. A lab extract blocked sugar-digesting enzymes in test tubes, so people on diabetes medicines should ask a clinician.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-25
- Last substantive update
- 2026-10-25
- How we research
- We read PubMed records for five papers: abstracts for all five (one genus review whose full text we also read, one Polish three-bolete survey whose tables we also read, one caesium processing study whose full text we also read, one composition and antibacterial paper, one lab enzyme paper). We also read the Penn State Extension guidance page in full and checked the name in GBIF. Index Fungorum, EFSA, FDA and poison-centre statements were not read, and the genus review's own sources on poisoning were not opened. Certainty ratings are the compiler's own reading.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. This page is information, not a recommendation to eat wild mushrooms.
Sources 7
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Budau R, Vicas SI, Bei MF, et al. The Genus Leccinum: Global Advances in Taxonomy, Ecology, Nutritional Value, and Environmental Significance.. Journal of Fungi. 2026. PMID 41590482. DOI 10.3390/jof12010070. (abstract and full text)
- Falandysz J, Meloni D, Fernandes AR, Saniewski M. Effect of drying, blanching, pickling and maceration on the fate of (40)K, total K and (137)Cs in bolete mushrooms and dietary intake.. Environmental Science and Pollution Research. 2022. PMID 34338984. DOI 10.1007/s11356-021-15523-9. (abstract and full text)
- Ferraro V, Spagnoletta A, Rotondo NP, et al. Hypoglycemic Properties of Leccinum scabrum Extracts-An In Vitro Study on alpha-Glucosidase and alpha-Amylase Inhibition and Metabolic Profile Determination.. Journal of Fungi. 2024. PMID 39452670. DOI 10.3390/jof10100718. (abstract)
- GBIF. GBIF Backbone Taxonomy: Leccinum scabrum (Bull.) Gray (usage key 9141390), checked 2026-10-25. GBIF API. 2026. (record)
- Gargano ML, Balenzano G, Venturella G, et al. Nutritional contents and antimicrobial activity of the culinary-medicinal mushroom Leccinum scabrum.. Mycology. 2025. PMID 40083412. DOI 10.1080/21501203.2024.2342519. (abstract)
- Penn State Extension. Penn State Extension: Preparing and Preserving Mushrooms. extension.psu.edu. 2024. (full text)
- Sotek Z, Malinowska K, Stasinska M, Ochmian I. Bioactive Compounds and Antioxidant Activity of Boletus edulis, Imleria badia, Leccinum scabrum in the Context of Environmental Conditions and Heavy Metals Bioaccumulation.. Molecules. 2025. PMID 40807452. DOI 10.3390/molecules30153277. (abstract and full text tables)
