Shukla, P. K., Khanna, V. K., Ali, M. M., Maurya, R., Khan, M. Y., and Srimal, R. C. Neuroprotective effect of Acorus calamus against middle cerebral artery occlusion-induced ischaemia in rat. Hum.Exp Toxicol 2006;25(4):187-194.

May 22, 2026 - Use of calamus and its extracts is prohibited in the United States. Clinical studies are lacking to provide dosing recommendations. Contraindications have not been identified, but use in the United States is prohibited. Avoid use. Adverse effects (emmenagogic and genotoxic activity) have been documented. None well documented. Clinical studies are lacking due to concerns of toxicity.

July 23, 2024 - Beta-asarone levels range from ... studies have raised concerns about potential liver toxicity, reproductive toxicity, and carcinogenic effects at high doses of beta-asarone....

Furthermore, saponin rich extract of the plant ameliorates the CCI-induced nociceptive pain threshold, sciatic functional and biochemical changes in a dose dependent manner [39,40]. As such this plant is not toxic; the ethanolic extract of this plant did not show any morphological, biological ...

July 1, 2026 - Acorus calamus (also called sweet flag, sway or muskrat root, among many other common names) is a species of flowering plant. It is a tall wetland monocot of the family Acoraceae, in the genus Acorus. Although used in traditional medicine over centuries to treat digestive disorders and pain, it has no clinical evidence of safety or efficacy and may be toxic ...

August 16, 2025 - Calamus is not considered safe for long-term internal use due to beta-asarone’s potential toxicity. Most countries restrict calamus supplements.

January 1, 2012 - However, there is no toxicological information available regarding its safety after exposure. The present study was designed to evaluate potential toxicity of an ethanolic extract of Acorus calamus Linn.

Another herb that seems to have been labeled as toxic by the powers that be. The reason behind this is unclear though, as there is no scientific evidence or any verified reports of Calamus toxicity.

April 2, 2026 - It is important to note that while the FDA has recorded zero adverse events and zero recalls specifically attributed to calamus oil, this likely reflects both the prohibition's effectiveness and the difficulty in attributing chronic health effects to specific additives in retrospective surveillance systems. ... - Studies from the 1970s-1980s demonstrating mutagenic properties of asarone in Ames bacterial assays · - Chronic toxicity studies in rats and mice showing organ effects and potential carcinogenic potential

March 31, 2026 - Importantly: Reliable clinical studies on dosage are largely lacking. Drugs.com puts it bluntly: Due to toxicity concerns and a lack of clinical data, calamus cannot be recommended for any purpose; in the U.S., its use and addition to food are prohibited.

February 1, 2018 - This review article summarizes the current knowledge of the chemical composition of different parts of A. calamus and their roles in the prevention and treatment of cardiovascular diseases. However, as no human studies have been performed, the review only includes in vitro and animal studies. The paper also briefly reviews the toxicity of A.

Preparations of the plant Acorus calamus (calamus or sweet flag) (A. calamus) are available via internet trade and marketed as being hallucinogenic. In 2003-2006, the Swedish Poisons Information Centre received inquiries about 30 clinical cases of intentional intoxication with A. calamus products.

July 18, 2016 - However, it is reported by several resources that the thick yellow paste is extremely toxic in nature. In certain parts of Europe, calamus was used as a digestive aid because it helped with conditions like dyspepsia, acidity, and heartburn.

June 11, 2021 - Shukla, P. K., Khanna, V. K., Ali, M. M., Maurya, R., Khan, M. Y., and Srimal, R. C. Neuroprotective effect of Acorus calamus against middle cerebral artery occlusion-induced ischaemia in rat. Hum.Exp Toxicol 2006;25(4):187-194.

November 6, 2024 - European calamus, which has lower beta-asarone content, is sometimes considered safer, but its use is still advised with caution. High doses or extended use are not recommended, especially in children or pregnant women. Due to its potential toxicity, dosing for calamus should be approached cautiously.

April 8, 2026 - While calamus has long been used for its fragrance and consumed by people, it has not been tested through rigorous clinical research. Individual medical reports of toxicity note severe nausea and prolonged vomiting lasting many hours after oral use.

September 6, 2012 - Overall, the findings of this study indicate that, HAE-AC is non-toxic and has at high dose, a mild but acceptable toxicity potential.

April 16, 2025 - Studies have shown that β-asarone, ... in several countries.[8] Studies have also shown that high doses of Oil of Calamus can cause severe nausea and prolonged vomiting, highlighting its potential toxicity.[9]...

Certain calamus varieties contain beta asarone, which was found to be "procarcinogenic" in animal studies [link]. Though certain varieties of calamus may be safer than others, calamus for sale is typically not labelled as to which type it is, and thus should be assumed to be dangerous to use ...