Evidence-based·Last reviewed May 31, 2026·How we grade evidence

Quebracho

BotanicalBest with a meal

Bark of South American trees with a long folk-medicine history for asthma and shortness of breath. Modern human evidence is essentially absent — almost everything is in-vitro or animal work on its alkaloids (related to yohimbine) and tannins. Not a substitute for evidence-based asthma or COPD therapy.

Quick decision guide

May help most

People curious about a traditional South American botanical with a long history of respiratory use — not a recommended therapy.

Common dosing range

No established human dose. Supplements typically supply 50–250 mg bark extract per serving.

When to expect effects

Not established — no modern human trials.

Watch out for

Some quebracho preparations contain yohimbine-type alkaloids that can raise blood pressure, cause anxiety, and interact with antidepressants.

Evidence snapshot

Asthma / bronchitis (traditional use)Mechanism only

Cardiometabolic effects (in vitro)Preclinical

Any modern human RCT outcomeNo data

What is it

Quebracho refers to the bark of South American trees, primarily Aspidosperma quebracho-blanco (white quebracho) and Schinopsis lorentzii (red quebracho). The bark is rich in condensed tannins and indole alkaloids and has long been used both industrially as a tanning agent and in traditional medicine.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You're researching traditional Argentine, Chilean or Paraguayan herbal medicine for context

You've discussed it with a clinician familiar with bronchodilator botanicals and want to try a short, low-dose course

Probably skip if…

You have asthma or COPD — use evidence-based inhalers, not quebracho

You take an MAOI, SSRI, SNRI, or other antidepressant — yohimbine-type alkaloids interact

You have hypertension, an anxiety disorder, or a cardiac arrhythmia

You're pregnant or breastfeeding

You want a stimulant-style fat burner — the closely related yohimbe is a more characterised (and risky) option

Evidence at a glance

Goal	Effect	Best fit	Time
Asthma and shortness of breath (traditional use) Mixed Evidence	Not quantified in modern trials	No clearly identified population — traditional use only	Not established
Blood-sugar and metabolic effects Mixed Evidence	Enzyme inhibition in vitro only	Not established in humans	Not established
Sexual function / erectile concerns Mixed Evidence	Not quantified in human trials	No established human evidence	Not established

Asthma and shortness of breath (traditional use)

Mixed Evidence

Effect: Not quantified in modern trials
Best fit: No clearly identified population — traditional use only
Time: Not established

Blood-sugar and metabolic effects

Mixed Evidence

Effect: Enzyme inhibition in vitro only
Best fit: Not established in humans
Time: Not established

Sexual function / erectile concerns

Mixed Evidence

Effect: Not quantified in human trials
Best fit: No established human evidence
Time: Not established

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Asthma and shortness of breath (traditional use)

Mixed Evidence

Aspidosperma quebracho-blanco bark has a long folk-medicine reputation in South America as a remedy for asthma, bronchitis, and dyspnea. Aspidospermine and related alkaloids relax airway smooth muscle in animal preparations, which is the mechanistic rationale. There are no modern randomised trials in humans, and the historical case-series literature is too low-quality to support recommending it over inhaled bronchodilators.

Effect size

Not quantified in modern trials

Time to effect

Not established

Best fit

No clearly identified population — traditional use only

Less likely

Anyone managing diagnosed asthma or COPD — proven inhaler therapy is far safer and more effective

Bottom line: Mechanism + folk-use story, no modern evidence. Don't substitute for proven asthma medications.

SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma Souza et al. (PMC3978231) — PMC — Brazilian Journal of Pharmacognosy

Blood-sugar and metabolic effects

Mechanism only

Mixed Evidence

In vitro work shows quebracho-blanco extracts inhibit dipeptidyl peptidase IV (DPP-IV) and alpha-glucosidase — enzymes targeted by some diabetes drugs (sitagliptin, acarbose). No human trials have tested whether oral quebracho lowers blood glucose or HbA1c.

Effect size

Enzyme inhibition in vitro only

Time to effect

Not established

Best fit

Not established in humans

Less likely

People with diabetes — use medications with established human evidence

Bottom line: Interesting in a test tube; nothing to act on clinically.

SourceSouza et al. (PMC3978231) — PMC — Brazilian Journal of Pharmacognosy

Sexual function / erectile concerns

Mechanism only

Mixed Evidence

Some quebracho preparations are marketed with libido and erectile-function claims because the bark contains alkaloids structurally related to yohimbine (an alpha-2 adrenergic antagonist). Quebracho itself has not been tested in modern erectile-dysfunction RCTs — the marketing piggybacks on yohimbe research, which has its own efficacy and safety controversies.

Effect size

Not quantified in human trials

Time to effect

Not established

Best fit

No established human evidence

Less likely

Anyone with hypertension, anxiety, or who takes serotonergic antidepressants

Bottom line: Marketing claim built on a sibling botanical's research; not validated for quebracho itself.

SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma NIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

How it works

Quebracho bark contains high concentrations of condensed proanthocyanidins (tannins) that bind to proteins, including dietary and microbial proteins in the digestive tract. This is the proposed basis for its traditional use in respiratory and gastrointestinal complaints. White quebracho also contains the alkaloid yohimbine and related indole compounds, which act as alpha-2 adrenergic receptor antagonists. In ruminant agriculture, condensed tannins from quebracho have been studied as feed additives to alter rumen fermentation and reduce methane production. In humans, well-controlled clinical trials are scarce, and most claims rest on traditional use, laboratory work, or animal data.

How to take it

1. Typical dose

• No established human dose for quebracho bark or its extracts • Commercial capsules typically list 50–250 mg of bark or extract per serving • Standardisation (to alkaloids or tannins) varies wildly between products

2. Higher studied dose

Not characterised — there are no modern dose-finding human trials.

3. Timing

Take with food to reduce stomach upset from the tannin content. Avoid taking near bedtime if a particular product contains yohimbine-type alkaloids — they can cause insomnia and tachycardia.

4. With food

With food (tannins are harsh on an empty stomach).

5. Split dosing

Not studied. If trying it, a single small daily dose makes side-effects easier to attribute.

6. How long to try

Time-limited (a few weeks at most) and only with clinician oversight if you have any cardiovascular, mental-health or respiratory diagnosis.

What to track

Resting blood pressure and heart rate (especially if the product is alkaloid-rich)

Sleep quality and anxiety symptoms

GI tolerance — tannins can cause cramping and constipation

Respiratory symptoms if you're trying it for breathing complaints — and don't stop your inhaler

Bottom line: There's no evidence-based dose. If you try it anyway, take a small amount with food and watch your blood pressure, heart rate, and sleep.

4 commercial forms

Compare the main delivery options and what they’re best suited for.

Aspidosperma quebracho-blanco bark powder

Traditional

The form referenced in 19th–20th-century South American materia medica for respiratory complaints. Tannin-heavy and harsh on the stomach when taken alone.

Variable; alkaloid and tannin content depend on bark source.

Alcohol or hydroethanolic extract

Concentrated

Concentrates the alkaloid fraction (aspidospermine, quebrachamine, yohimbine analogues) and reduces tannin bulk. Carries proportionally higher cardiovascular and CNS risk.

Higher alkaloid exposure than crude bark.

Aqueous decoction (tea)

Folk preparation

The most common traditional preparation. Extracts more tannin and less alkaloid than an alcohol extract, which is why it's perceived as gentler.

Lower alkaloid content than ethanolic extracts.

Schinopsis (red quebracho) extract

Not for supplements

Industrial tannin source for leather production and ruminant feed-additive studies. Not the species used in human folk medicine and not appropriate as an oral supplement.

Predominantly condensed tannins; not formulated for human consumption.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

nauseastomach upsetconstipation (tannins)metallic tasteheadacheanxiety or jitteriness (alkaloid-rich products)

Serious risks

Quebracho bark contains indole alkaloids structurally related to yohimbine. Yohimbe products are linked to dangerous blood-pressure spikes, panic attacks, tachycardia, and serious cardiac events at supplement doses — quebracho preparations standardised to alkaloid content carry the same theoretical risk.
SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements
Tannin-rich plant material can sharply reduce absorption of dietary iron and several drugs taken at the same time.
SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma

Who should avoid it

People with hypertension, heart disease, an anxiety disorder, or any psychiatric condition — yohimbine-type alkaloids can destabilise all four.
SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements
Anyone on an MAOI, SSRI, SNRI, tricyclic antidepressant, sympathomimetic stimulant, or naloxone — risk of hypertensive or serotonergic reactions.
SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements
People on iron supplements or any medication where reduced absorption could matter (thyroid hormone, antibiotics) — separate by several hours.
SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma
People with diagnosed asthma or COPD — don't use quebracho instead of a prescribed bronchodilator.
SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma

Pregnancy & breastfeeding

Avoid in pregnancy and while breastfeeding. There are no human safety data, and the yohimbine-type alkaloids that may be present have known cardiovascular and uterine effects.

SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

Bottom line: Treat any quebracho product like a yohimbe-adjacent supplement: avoid if you have heart, blood-pressure, or psychiatric concerns, and don't use it as a substitute for proven asthma therapy.

Interactions

MAOI antidepressantsMajor

Yohimbine-type alkaloids in quebracho can cause hypertensive crisis when combined with monoamine oxidase inhibitors.

SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

SSRIs / SNRIs / tricyclic antidepressantsModerate

Adrenergic and serotonergic effects of yohimbine-type alkaloids can compound antidepressant side effects (anxiety, hypertension, in rare cases serotonin syndrome).

SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

stimulants (caffeine, sympathomimetics)Moderate

Additive cardiovascular and anxiogenic effects with alkaloid-rich quebracho preparations.

SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

antihypertensive medicationsModerate

Alkaloid-rich quebracho can raise blood pressure and counteract antihypertensive therapy.

SourceNIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements

iron supplementsMinor

Tannins bind dietary and supplemental iron in the gut, reducing absorption. Separate by 2 hours.

SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma

thyroid hormone and oral antibioticsMinor

Tannins can reduce absorption of multiple oral drugs taken at the same time. Separate by 2–4 hours.

SourceMemorial Sloan Kettering About Herbs — MSKCC — Aspidosperma

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Botanical source clearly identified — Aspidosperma quebracho-blanco (white quebracho, bark) is the medicinal species; Schinopsis red quebracho is the leather-tanning material and not appropriate for supplements

Standardisation disclosed — total alkaloid percentage AND condensed-tannin content (so you know roughly what you're taking)

Third-party identity testing for the bark (DNA or HPLC-fingerprint) — there's no pharmacopoeial monograph

Small dose per capsule (50–100 mg) so you can titrate cautiously

Be skeptical of…

Asthma, COPD, or 'natural bronchodilator' claims — there are no modern human trials supporting this

Diabetes or 'blood-sugar control' claims — only in-vitro DPP-IV / alpha-glucosidase data exist

Erectile or libido claims — these borrow from yohimbe marketing, not quebracho evidence

Combined yohimbe + quebracho 'fat-burner' stacks — stacking alkaloid-rich extracts increases the chance of a cardiovascular adverse event

Products that don't disclose the species or which plant part was used

Frequently asked questions

Does quebracho contain yohimbine?⌄

Yes. White quebracho bark contains yohimbine and related indole alkaloids. The amount varies by preparation, and this is the source of most concerns about side effects.

Is quebracho safe for weight loss?⌄

Quebracho is sometimes marketed for fat loss because of its yohimbine content, but evidence in humans is weak and the risks of stimulant-like side effects are real.

Can I drink quebracho tea?⌄

Traditional preparations exist, but tannin content is high and may irritate the stomach. Pregnant women and people on medications should avoid it.

How is quebracho different from yohimbe?⌄

Both contain yohimbine. Yohimbe is the bark of Pausinystalia johimbe (an African tree), while quebracho is a South American tree. Alkaloid profiles differ.

Is quebracho regulated?⌄

It is sold as a dietary supplement in many countries with limited regulation. Some authorities have restricted yohimbine-containing products.

References by claim

Asthma and shortness of breath (traditional use)

Memorial Sloan Kettering About Herbs — MSKCC — Aspidosperma link

Souza et al. (PMC3978231) — PMC — Brazilian Journal of Pharmacognosy (2014) link

Sexual function / erectile concerns

NIH ODS Yohimbe Health Professional Fact Sheet — NIH Office of Dietary Supplements link

Other references

Aspidosperma quebracho-blanco on Wikidata — Wikidata link

Quebracho on NIH DSLD — NIH Dietary Supplement Label Database link

Track Quebracho with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store

Evidence-based·Last reviewed May 31, 2026·Evidence current as of May 31, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.