Sweet Vernal Grass

Scientific Name(s): Anthoxanthum odoratum L.
Common Name(s): Grass, Spring grass, Sweet vernal grass

Medically reviewed by Drugs.com. Last updated on Jul 22, 2021.

Clinical Overview

Use

Sweet vernal grass is used as a flavoring agent and sometimes in the manufacturing of brandy. Due to poisoning in cattle fed hay made from sweet vernal grass, use in humans is discouraged. A sublingual tablet containing an allergen extract of sweet vernal, orchard, perennial rye, and Kentucky blue grass (Oralair) is US Food and Drug Administration (FDA)–approved to treat allergic rhinitis caused by grass allergens.

Dosing

There is no clinical evidence to support specific dosing recommendations. Caution should be exercised because of the plant's high coumarin content; when the plant material is not dried properly, dicoumarol (a derivative of coumarin) may form, which can interfere with clotting.

Contraindications

No longer considered safe.

Pregnancy/Lactation

Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

In cattle, ingestion of hay made from sweet vernal grass caused progressive weakness, stiff gait, breathing difficulties, and hemorrhage followed by quick death. This reaction, attributed to the dicoumarol content of the hay, suggests that human consumption can be dangerous. Pollen from sweet vernal grass can cause allergic rhinitis, conjunctivitis, and asthma.

Toxicology

Beyond historical references to the use of sweet vernal grass as a flavoring agent, no pharmacological or toxicological studies are available.

Scientific Family

• Poaceae (grass)

Botany

Sweet vernal grass is a perennial native to Eurasia and Africa but also commonly found in American fields, pastures, and waste places as far north as southern Ontario and as far south as Louisiana. It is a fragrant plant in the Poaceae family that grows in tufts, without stolons or basal scaly offshoots, and has flat leaves and narrow spike-like panicles of proterogynous flowers. The culms are slender, erect, and 2 to 10 dm in height. The brownish-green spikelets are 8 to 10 mm long and spread at the time of flowering.Fernald 1950

History

Sweet vernal grass has been used as a flavoring agent because of its vanilla-like aroma. In Russia and neighboring countries, it was used in the manufacturing of brandy.Hocking 1955 In Norway, sweet vernal grass was among the scented grasses used as perfume and for storing with clothing.Alm 2015 Some North American Indian tribes used sweet vernal grass to flavor tobacco and to make baskets, mostly due to its scent rather its suitability as a basketry material. In Russia, the grass is used as a flavoring agent in tobacco.Alm 2015

Chemistry

Although the presence of dicoumarol has been detected in sweet vernal grass hay, few chemical studies of sweet vernal grass have been conducted.Pritchard 1983 The sweet scent of the plant is attributed to its high coumarin content.Alm 2015

Uses and Pharmacology

Animal data

An outbreak of hemorrhagic diathesis in cattle fed sweet vernal grass hay has been reported. This effect was later reproduced experimentally in calves fed the same hay.Pritchard 1983 The poisoning was characterized by increased prothrombin and partial thromboplastin times, with leukocyte and erythrocyte counts remaining in the normal range until terminal hemorrhage occurred. Symptoms inc...