What is Calamus?
Calamus gets its name from the Greek word for reed, calamos.
The plant goes by many other names, including cinnamon sedge, myrtle grass, myrtle sedge, sweet calamus, sweet cane, sweet flag, sweet root, sweet rush, sweet sedge and its botanical name, Calamus aromaticus.
The plant is about two percent essential oil, which comes mainly from the rhizomes through steam distillation. Sometimes the leaves are used to produce oil, but rarely. As such, you may hear the oil referred to as calamus root essential oil.
Calamus is native to India. The oil is produced there and in Russia, as well as in smaller amounts in parts of Europe, Siberia, and China. Poland and Yugoslavia produce calamus oil with a scent considered to be more uniform and long-lasting.
Another plant, the yellow flag iris, resembles calamus. However,the two are botanically unrelated. Other aromatic sedge varieties can be found in India and are also used in perfumes and medicine, such as Calamus odoratus.
Calamus oil is thick and has a yellow hue. Poor quality oil will have a more camphorous note.
The better quality calamus oil, with its refreshing cinnamon-like scent, blends well with Amyris (Amyris balsamifera), Cinnamon (Cinnamomum zeylanicum), Atlas Cedarwood (Cedrus atlantica), and others.
Calamus Essential Oil Uses
Calamus oil is used in cosmetics and perfumes, scenting woody or leathery fragrances. It is a base note, providing a medium strength fixative anchor for spicy or oriental perfumes and colognes.
Due to the beta asarone content, the oil should not be used by anyone at home. Beta asarone, also known as cis-isoasarone, is highly toxic when swallowed and is carcinogenic. The chemical is also a danger to aquatic environments. 
Depending on where the oil is produced, the percentage of asarone can be extremely high or rather low. Russian calamus only has around six percent, while Indian calamus can reach 80-90 percent or more.
There is a North American variety of calamus that has none of this in it. Either way, it is not safe for anyone not trained in its use, as it can be extremely difficult to determine which type you have.
The oil also contains a small percentage of eugenol, which is likely where the yellowish tint and spicy scent of the oil comes from.
Methyl eugenol has been known to cause skin sensitization and can be hazardous in other ways as well. It is carcinogenic and can cause genetic defects. 
Food and Beverage
Calamus essential oil has been used as a flavoring for the food and beverage industry for beer, tonics, tooth powders, and more. It is still utilized in some parts of the world.
However, the plant, root, extracts, and oil are all banned from use in the United States. 
As an herb, calamus has been used in many ways. For instance, ancient Egyptians used the plant for its aphrodisiac effects. Later on, Asians utilized the root for the same reason.
The plant was mentioned in the Bible as well. It was mentioned in Exodus as an ingredient of the anointing oil. In other portions of the book, it was called 'sweet cane.'
Historical Medicinal Uses
It is estimated that calamus has been used for around 4,000 years in a variety of ways. The healing properties of the plant are attributed to its volatile oils.
Throughout Europe, calamus was considered a 'wonder drug.' It was commonly used as a sedative and nervine.
The Indian people value calamus as a traditional medicine. There as well as in Turkey, you can buy candied calamus rhizomes to help alleviate bronchial and digestive complaints.
It has also been used in the following ways:
- Native Americans created remedies for colic, digestion issues, and fevers using calamus.
- The Turkish people use it to combat infections.
- In China, the plant is used to treat hearing problems, vertigo, and epilepsy.
- People throughout Europe use the herb for intestinal upset and to aid digestion.
In the British Herbal Pharmacopoeia, calamus is still listed as a treatment for 'acute and chronic dyspepsia, gastritis, intestinal colic, anorexia, and gastric ulcer.' 
Vacha is the name for calamus in traditional Ayurveda. Ayurvedic practitioners have used the aromatic herb for centuries for a variety of ailments, ranging from expelling intestinal worms to aiding memory. 
Calamus Essential Oil Benefits and Dangers
The side effects and dangers of using calamus essential oil far outweigh calamus root benefits.
On WebMD, there is a long list of side effects from the plant and its oils: 
- Calamus may worsen heart conditions.
- It can lower the heart rate and blood pressure, making it dangerous for people already suffering from hypotension.
- Calamus has sedative effects and can cause excess sleepiness as well as interfere or exacerbate medications from surgery.
- Symptoms of calamus toxicity include dizziness, shaking, seizures, and kidney damage.
Calamus may also interfere with certain drugs.
Particularly, the effects of drying medications like antihistamines, other allergy medications, atropine, scopolamine, and even antidepressants may be lessened when used in conjunction with the herb or its oil.
The plant and its oil are emmenagogues, meaning they could stimulate menses. They should never be used during pregnancy. Being genotoxic, they also may mutate cells.
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Calamus Essential Oil Research, Facts, and Studies
There is not a lot of studies that readily apply to humans on calamus. Many of them show the effects of the plant's oil being effective against various microbes. However, there was one promising study of interest:
Gastric Cancer Cells
A study in 2017 found that calamus oil was effective in combating cancer cell growth and proliferation in vitro. This is not to say that the plant or its oil is effective against cancer, as much more research needs to be performed before such a conclusion can be made. 
Calamus has been used in different ways for thousands of years throughout history.
The volatile oil, which is mainly found in the rhizomes of the mud-loving plant, is responsible for medicinal and aromatic qualities of calamus.
Depending on where the plant grew and where the oil was produced, the percentage of this constituent can be as high as 80 percent. It is an oral and dermal toxin and a known carcinogen, and thus should be avoided.
Even though the oil has quite a few potent capabilities, it should not be used in aromatherapy or by home users due to the potential beta-asarone content.
- British Herbal Pharmacopoeia 1983, p.14