Calamus

Botanical

What is it

Calamus (Acorus calamus, sweet flag) is a perennial wetland plant with a long history in Ayurvedic, Chinese, and Western herbal traditions. The rhizome has been used for digestive complaints, cognitive support, and anxiety. However, certain calamus types contain beta-asarone, which is genotoxic and carcinogenic, leading to regulatory restrictions.

Evidence for 1 use

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

Traditional cognitive / digestive uses

Mixed Evidence

Strong traditional use but no rigorous modern clinical trials. Safety concerns outweigh limited evidence for benefits.

How it works

Acorus calamus rhizome contains essential oils, with the beta-asarone content varying by genetic variety: Indian and European types are high in beta-asarone (and considered unsafe), while North American calamus (var. americanus) is essentially free of beta-asarone. Other compounds include alpha-asarone, sesquiterpenes, and tannins. Traditional uses include digestive support, memory enhancement (with empirical use in Ayurveda as a 'medhya' or intellect-promoting herb), and sedation. The closely related Acorus gramineus is used in Chinese medicine and has different chemistry.

Dosage

Use of high-beta-asarone calamus is not recommended. North American or jatamansi-free preparations: 1-3 g of dried rhizome as tea, or 1-3 mL of tincture, 2-3 times daily.

When and how to take it

Not applicable - use is restricted in the US. Traditional preparations follow practitioner-specific guidance.

2 commercial forms

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

Acorus calamus rhizome (high beta-asarone)

Not recommended for use.

Banned by FDA in foods/supplements

Acorus calamus var. americanus

Limited availability and use.

Lower beta-asarone but still restricted

Safety

FDA has banned Acorus calamus from foods and supplements due to beta-asarone genotoxicity. Some herbal products may use North American variety (lower beta-asarone), but the FDA ban is broad. Risks include genotoxicity, carcinogenicity, neurotoxicity at high doses, and cardiac effects.

Who should be cautious

Generally not recommended due to FDA restrictions. Absolutely avoid in pregnancy, lactation, children, and people with seizure disorders. Avoid all high-beta-asarone preparations.

Interactions

Theoretical interactions with CNS depressants, antiepileptics, and cardiac medications.

Frequently asked questions

Is calamus banned?⌄

Yes, FDA has banned Acorus calamus from foods and supplements due to beta-asarone toxicity concerns.

Are all calamus species toxic?⌄

North American Acorus calamus var. americanus has very low beta-asarone, but the regulatory ban applies broadly.

References

Calamus on Wikidata — Wikidata link

Calamus on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Calamus (PubMed search) — PubMed link

Track Calamus with Pilora

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

Coming to App Store
Evidence-based·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.