Sweet Flag (Acorus calamus) – The Complete Guide

Sweet Flag

Acorus calamus, also known as the Sweet Flag, is a plant that grows in wetland areas.

It’s part of the Acoraceae family and has been used for many years in traditional medicine.

However, there is no clinical proof that it’s safe or effective, and it might even be toxic.

In the United States, the use of calamus is banned for commercial purposes.

Description of Sweet Flag

This plant is a herbaceous perennial that can grow up to 79 inches (2 meters) tall.

Its leaves are similar to those of the iris family, with a sword-like shape and parallel veins.

The leaves are yellowish-brown and have smooth edges, which can be wavy or crimped.

Sweet flag is different from iris plants because of the crimped edges of the leaves, the sweet smell it gives off when crushed, and the presence of a spadix.


Only the Sweet Flag plants that grow in water have flowers. The triangular, solid flower-stems come out from the outer leaves’ axils.

A semi-erect spadix can be seen on one side of the flower stem. The spadix is solid, cylindrical, tapers at each end, and is 5 to 10 cm long.

Tiny greenish-yellow flowers densely cover the spadix.

Each flower has six petals and stamens, surrounded by a perianth with six divisions. The flowers give off a sweet fragrance.

Range and Habitat of Sweet Flag

Sweet flag is found in many parts of the world, such as India, central Asia, southern Russia, Siberia, Europe, and North America.

It grows in wetland habitats like the edges of lakes, ponds, rivers, marshes, swamps, and other wetlands.

Names and Etymology

There are many common names for Acorus calamus, including Beewort, Bitter Pepper Root, Calamus Root, Flag Root, Gladdon, Myrtle Flag, Myrtle Grass, Myrtle Root, Myrtle Sedge, Pine Root, Sea Sedge, Sweet Cane, Sweet Cinnamon, Sweet Grass, Sweet Myrtle, Sweet Root, Sweet Rush, Sweet Sedge, and Wada Kaha.

The name ‘Sweet Flag’ comes from the plant’s sweet scent and its resemblance to the iris species.

The Latin word “acorus” is derived from the Greek word for pupil, as the plant’s root juice was once used as a remedy for eye diseases.

History of Sweet Flag

The use of Sweet Flag dates back to ancient times, with mentions in Egyptian papyrus dating to around 1300 BC.

The Egyptians mainly used the plant to make perfumes. Europeans confused the identity of the Acorus calamus with their native Iris pseudacorus, leading to some confusion in early literature.

The plant was introduced to Britain in the late 16th century.

Botany of Sweet Flag

There are three forms of the Sweet flag, distinguished by their chromosome numbers: diploid, triploid, and tetraploid.

The triploid form is the most common and is thought to have originated in the Himalayan region.

The different forms are found in various parts of the world, and the taxonomic position of these forms is still debated.

Chemistry of Sweet Flag

The leaves and rhizomes of Sweet Flag contain a volatile oil that gives the plant its characteristic odor and flavor.

The oil is made up of various components, such as beta-asarone, methyl isoeugenol, and alpha-asarone.

The plant’s phytochemicals can vary depending on factors like geographic location, plant age, climate, and species variety.

Safety and Regulations

In 1968, the United States Food and Drug Administration banned Sweet Flag and products derived from it for use as human food or as a food additive.

The European Commission has also recommended limits on its consumption, but the degree of safe exposure remains undefined.

Toxicity of Sweet Flag

There have been individual reports of toxicity from the use of Sweet Flag, with symptoms like severe nausea and prolonged vomiting.

Laboratory studies also indicate other forms of toxicity, mainly due to the compound ß-asarone.

Uses of Sweet Flag

Sweet flag has been used for various purposes throughout history, including medicinal uses, as a flavoring for food, and in the perfume industry.

The plant’s young stalks can be eaten raw, and its roots can be made into candy.

In herbal medicine, Sweet Flag has been used by various cultures to treat different ailments, such as gastrointestinal diseases and pain.


Sweet Flag is sometimes used as a pond plant in horticulture, and there are ornamental cultivars available.


The dried and pulverized roots of the Sweet Flag contain a compound that is useful as an insecticide.

Scientific Classification

Scientific Name:Acorus calamus
Also Known As:Sweet Flag, Sway, Muskrat Root, Beewort, Bitter Pepper Root, Calamus Root, Flag Root, Gladdon, Myrtle Flag, Myrtle Grass, Myrtle Root, Myrtle Sedge, Pine Root, Sea Sedge, Sweet Cane, Sweet Cinnamon, Sweet Grass, Sweet Myrtle, Sweet Root, Sweet Rush, Sweet Sedge, Wada Kaha
Conservation Status:Least Concern

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