Acorus calamus (Vacha)

About

What it is and where it shows up.

Vacha (Acorus calamus Linn.) is a perennial aromatic herb whose rhizome has been used for millennia in Ayurvedic and Chinese traditional medicine for neurological, gastrointestinal, and respiratory disorders. Its rhizome oil — rich in the phenylpropanoid β-asarone — has historically been employed as a flavouring, digestive stimulant, and nootropic agent.

Safety summary

The regulatory and scientific consensus.

The primary safety concern is β-asarone, a phenylpropanoid constituent of the rhizome oil that has demonstrated carcinogenic, hepatotoxic, cardiotoxic, mutagenic, and reproductive toxic properties in animal studies. The β-asarone content varies critically by geographic chemotype/ploidy: the Indian tetraploid variety (~75% β-asarone) poses the highest risk, while the North American diploid variety is essentially β-asarone-free. No formal ADI has been established; the FDA banned all calamus-derived food additives in 1974, and the EU prohibits its use as a flavouring/seasoning.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
Health Canada (Canada)	Banned	Use of calamus oil in food is prohibited in Canada, consistent with the US position on β-asarone toxicity.source
EFSA (European Food Safety Authority) (European Union)	Banned	β-asarone and calamus oil are prohibited for use as flavourings/seasonings in the EU. European scientific reviews concluded β-asarone is carcinogenic in rodents and should be minimised in food uses. Residue limits of 0.1 mg/kg in food/beverages and 1 mg/kg in spirits/spice snacks have been cited in older literature, but current EU Flavouring Regulation prohibits its deliberate use.source
FDA (Food and Drug Administration) (United States)	Banned	21 CFR 189.110 — Calamus and its derivatives are listed as substances prohibited from direct addition or use as human food. The ban was triggered by evidence of carcinogenicity (duodenal tumours) in rats following high-dose calamus oil exposure.source
FSSAI (Food Safety and Standards Authority of India) (India)	Restricted	FSSAI does not approve calamus oil as a direct food additive. Within the Ayurvedic system (regulated by Ministry of AYUSH), the Ayurvedic Pharmacopoeia of India mandates a classical Shodhana (detoxification/purification) process — boiling the rhizomes — before inclusion in Ayurvedic formulations, to reduce β-asarone content. Raw calamus is not sanctioned for unsupervised food use.source

Who should approach with care

Whose guidance would steer them away.

Pregnancy — β-asarone has demonstrated reproductive toxicity in preclinical studies, and the plant has historically been used as an abortifacient, making any exposure during pregnancy potentially harmful.

Lactation — No human safety data exists for β-asarone transfer into breast milk, and given its systemic toxicity profile (hepatotoxic, potentially genotoxic), use during lactation cannot be considered safe.

Infants — Despite traditional cultural practices of administering Vacha rhizome paste to infants for cognitive enhancement, the lack of safety data and high β-asarone content in Indian-variety rhizomes poses an unacceptable risk to infants.

Children — Children's developing hepatic and neurological systems are more vulnerable to β-asarone's CNS-inhibitory, sedative, and hepatotoxic effects; no paediatric safety threshold has been established.

Liver Disease — β-asarone induces unscheduled DNA synthesis in hepatocytes and has demonstrated hepatotoxicity in animal studies, making calamus use particularly dangerous in individuals with pre-existing liver disease.

Research citations

The sources behind this verdict.

1PubMed. Reporting negative Ames test results for Indian Acorus calamus L., rhizome, extracts, and beta asarone, 2024. pmc.ncbi.nlm.nih.gov
2PubMed. Quantitative Analysis of β-Asarone Derivatives in Acorus calamus and Herbal Food Products by HPLC-MS/MS, 2021. pubmed.ncbi.nlm.nih.gov
3PubMed. α-Asarone, β-asarone, and γ-asarone: Current status of toxicological evaluation, 2021. pubmed.ncbi.nlm.nih.gov
4PubMed. Role of Vacha (Acorus calamus Linn.) in Neurological and Metabolic Disorders: Evidence from Ethnopharmacology, Phytochemistry, Pharmacology and Clinical Study, 2020. pmc.ncbi.nlm.nih.gov
5PubMed. Is it safe to use Acorus calamus as a source of promising bioactive compounds in prevention and treatment of cardiovascular diseases?, 2018. pubmed.ncbi.nlm.nih.gov
6PubMed. Fate of β-asarone in Ayurvedic Sodhana process of Vacha, 2013. pmc.ncbi.nlm.nih.gov

Independently researched6 citations