Goldenseal (Hydrastis canadensis): Benefits, Dosage, Safety & Evidence

What is a herb–drug interaction?

A herb–drug interaction happens when a plant or supplement changes how a medication works in your body — making it stronger, weaker, or more likely to cause harm. Herbs contain active compounds that can speed up or slow down the enzymes and transporters your body uses to process drugs.

Why it matters

St. John's Wort can make birth control, antidepressants, and blood thinners less effective.

Garlic can increase bleeding risk with warfarin and other blood thinners (also ginkgo, ginger, and turmeric).

Kava can amplify sedation when taken with anxiety or sleep medications (also valerian).

The risk is highest for older adults, anyone taking several medications, and people with chronic conditions.

Always tell your doctor and pharmacist about every herb and supplement you take — and check below before combining.

Known Drug Interactions (2)

1 Severe1 Moderate

Drug	Severity	Description
Metformin	Moderate	Berberine in goldenseal may enhance blood sugar-lowering effects of metformin.
Cyclosporine	Severe	Goldenseal (berberine) may significantly increase cyclosporine blood levels, increasing toxicity risk.

This list reflects a curated subset of documented interactions and is not exhaustive. The absence of a drug here is not proof that it is safe to combine. Always confirm with a pharmacist or healthcare provider.

Frequently asked questions

How does goldenseal work to fight infections?

Goldenseal contains berberine and hydrastine, alkaloids with demonstrated antimicrobial properties. Berberine interferes with bacterial cell division and prevents pathogens from adhering to cell walls. It also stimulates immune cell activity and reduces inflammation. Hydrastine provides astringent effects that tighten mucous membranes, helping block pathogen entry. These combined mechanisms make goldenseal effective against bacteria, fungi, and certain parasites (Evidence Level B).

Can I take goldenseal while pregnant or breastfeeding?

Goldenseal is unsafe during pregnancy and breastfeeding. Berberine crosses the placenta and may cause uterine contractions, potentially leading to miscarriage or premature labor. It can also cause kernicterus, a type of brain damage, in newborns. Breastfeeding mothers should avoid goldenseal as berberine passes into breast milk. Women who are pregnant, nursing, or trying to conceive should not use goldenseal under any circumstances (Evidence Level B).

What medications does goldenseal interact with?

Goldenseal interacts with numerous medications due to berberine's inhibition of cytochrome P450 enzymes, particularly CYP3A4 and CYP2D6. This affects metabolism of cyclosporine, increasing toxicity risk. Goldenseal may enhance effects of blood thinners, antidiabetic drugs, blood pressure medications, and sedatives. It can also interfere with certain antidepressants and antifungal medications. Always consult a healthcare provider before combining goldenseal with prescription medications (Evidence Level B).

What is the recommended dosage for goldenseal supplements?

The standard adult dosage for goldenseal is 250-500mg of standardized extract taken three times daily, not exceeding three weeks of continuous use. For liquid extracts, 2-4mL of 1:2 extract or 5-10mL of 1:5 tincture three times daily is typical. Extended use beyond three weeks may reduce effectiveness and increase side effect risk. Dosage should be individualized based on health status and tolerance (Evidence Level B, Traditional).

What are the side effects of taking goldenseal?

Common goldenseal side effects include gastrointestinal upset, nausea, constipation, and mouth irritation. Some individuals experience photosensitivity, increasing sunburn risk. High doses may cause numbness, difficulty breathing, or liver strain. Goldenseal is contraindicated for those with hypertension, heart disease, liver disease, or G6PD deficiency. Long-term use can lead to reduced beneficial gut bacteria. Discontinue use if adverse symptoms occur (Evidence Level B, Traditional).

What is goldenseal used to treat?

Goldenseal is traditionally used for eye infections, digestive issues, respiratory infections, skin conditions, and wound care. Native American healers employed it for infections and inflammatory complaints. Modern use focuses on gastrointestinal infections, topical wound antisepsis, and upper respiratory support. Evidence supports antimicrobial and anti-inflammatory properties, though clinical trials remain limited. It is often combined with echinacea in immune-support formulations (Evidence Level B, Traditional).

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 27 PubMed articles · model: gemma4:31b

Summary

Goldenseal (Hydrastis canadensis) is a perennial plant native to eastern North America containing isoquinoline alkaloids, most notably berberine [PMID:37562957, PMID:30000926].

Background

Goldenseal (Hydrastis canadensis) is a perennial plant native to eastern North America [PMID:37562957]. It is commonly available as a dietary supplement in various forms, including capsules, pills, tablets, lozenges, liquids, and powders [PMID:30725649].

Traditional uses

Goldenseal has been traditionally used as an anti-infective both systemically and topically [PMID:30000926], and is used to treat skin infections [PMID:22814821], bacterial infections, and digestive problems [PMID:30031041].

Active compounds

The plant contains isoquinoline alkaloids, including berberine (the most abundant), hydrastine, canadine, palmatine, and hydrastinine [PMID:17645667, PMID:14640583]. It also contains flavonoids such as sideroxylin, 8-desmethyl-sideroxylin, and 6-desmethyl-sideroxylin [PMID:21661731].

Mechanism of action

Berberine exhibits anti-inflammatory and antioxidant activities in vitro [PMID:27671811]. Goldenseal extracts and specific flavonoids may act as efflux pump inhibitors (e.g., inhibiting the NorA pump in S. aureus), which synergistically enhances the antibacterial activity of berberine [PMID:21157683, PMID:21661731]. Additionally, leaf extracts have demonstrated quorum quenching activity against MRSA by attenuating signal transduction [PMID:22814821].

Clinical evidence

Evidence BMetabolic Health (Berberine)

Lipid-lowering and insulin-resistance improving actions have been demonstrated in numerous randomized clinical trials [PMID:27671811].

Evidence BType 2 Diabetes (Metformin Interaction)

A three-arm crossover study in adults with type 2 diabetes found no clinically meaningful interaction between goldenseal and metformin [PMID:39943692].

Safety & adverse effects

Goldenseal alkaloids (berberine, palmatine, hydrastine, and canadine) have shown phototoxicity to human keratinocytes, lens epithelial cells, and retinal pigment epithelial cells when exposed to UVA radiation [PMID:17645667, PMID:16780351, PMID:11712911].

Pregnancy & lactation

Goldenseal has been used topically by nursing mothers for sore nipples, but no data exist on its safety or excretion into breastmilk [PMID:30000926]. There is concern that berberine can displace bilirubin from serum albumin, potentially causing brain damage in newborn infants; therefore, most sources recommend avoiding exposure of neonates to goldenseal via breastfeeding or otherwise [PMID:30000926].

Drug interactions

Goldenseal is known to cause clinically important drug interactions [PMID:28762712]. It significantly inhibits human CYP3A activity in vivo [PMID:17495878] and inhibits various cytochrome P450 isoforms (CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A) in vitro [PMID:22224048]. It may inhibit intestinal uptake transporters (OCT3, PMAT, THTR2), which was shown to decrease metformin systemic exposure in healthy adults [PMID:37562957].

Evidence summary

Evidence consists primarily of in vitro studies, animal models, and a limited number of human clinical trials focusing on pharmacokinetic interactions and the effects of its primary alkaloid, berberine.

PubMed sources

1.PMID: 27671811 (2016) — Berberine and Its Role in Chronic Disease. · Advances in experimental medicine and biology
2.PMID: 28762712 (2017) — Common Herbal Dietary Supplement-Drug Interactions. · American family physician
3.PMID: 30000926 (2006) — Is it safe to consume traditional medicinal plants during pregnancy? · Phytotherapy research : PTR
4.PMID: 10767672 (2000) — Berberine. · Alternative medicine review : a journal of clinical therapeutic
5.PMID: 30725649 (2026) — Goldenseal (Hydrastis canadensis L.) and its active constituents: A critical review of their efficacy and toxicological issues. · Pharmacological research
6.

Goldenseal

Sources & Citations

Calculate a safe dose of Goldenseal

Tea Tree

Oregano

Black Walnut

⚠️ Not Recommended During Pregnancy or Nursing

2 Known Drug Interactions — Some May Be Serious

Contraindications

Possible Side Effects

What is a herb–drug interaction?

Known Drug Interactions (2)

Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Pregnancy & lactation

Drug interactions

Evidence summary

PubMed sources

Government sources

Goldenseal

Sources & Citations

Calculate a safe dose of Goldenseal

Related Herbs

Tea Tree

Oregano

Black Walnut

⚠️ Not Recommended During Pregnancy or Nursing

2 Known Drug Interactions — Some May Be Serious

Contraindications

Possible Side Effects

What is a herb–drug interaction?

Known Drug Interactions (2)

Frequently asked questions

Summary

Background

Traditional uses

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Pregnancy & lactation

Drug interactions

Evidence summary

PubMed sources

Government sources