Medicinal uses of Acorus calamus were popular among healing traditions around the globe, including Ayurveda, Unani, and Native American medicine. Calamus is a constituent herb in the Holy Anointing Oil referred to in the Bible. The rhizome and sometimes the leaves were used in medicines. For example, travelers routinely carried calamus-based healing oils to treat wounds caused by excessive walking.
When chewed or swallowed fresh, the rhizome stimulates the brain and nervous system, causing euphoria and a calming effect. It can also be dried, ground, pulverized, converted into capsule form, or mixed into a smoking blend with calamus, tobacco, and other herbs. In Europe, it was common to cover church and mansion floors with calamus foliage, as the fragrance helped to mask odors caused by poor sanitation and to deter insects.
The psychedelic properties of the plant are accepted in herbal therapies in Europe, China, and India. In Europe, the rhizome was added to wine and absinthe. In Latin America, it was used as a stimulant, similar to coca leaf. It was an ingredient of a hallucinogen called witches’ flying ointment throughout Europe.
North American tribes like the Sioux held the plant in great esteem. They planted calamus along migration paths and trails. They viewed it as a miracle plant that cured skin diseases, coughs, colds, asthma, and digestive disorders. They used it in face paint before battle for its stimulating and calming effects. Fragrant garlands were made from the plant too. Calamus was also extensively used by early American settlers.
The U.S. FDA banned A. calamus in 1968 when research indicated that some species of Acorus had carcinogenic chemicals. Research has shown that the North American variety, Acorus americanus, does not have the same carcinogenic chemicals as those found in A. calamus. Nevertheless, herbal shops in the United States no longer recommend or dispense products containing this plant.
In 1995, Health Canada listed the species as an “herb used as a non-medicinal ingredient in non-prescription drugs for human use.” Although the Canadian subspecies do not contain carcinogenic chemicals, the water of its habitats is often poisoned by hemlock (Cicuta maculata).