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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 Aug 1, 2019.

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Beyond historical references to the use of sweet vernal grass as a flavoring agent, no pharmacological or toxicological studies are available.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 included rapid onset of progressive weakness, mucosal pallor, stiff gait, tachypnea, tachycardia, and hematomata, quickly ending in death. Necropsy revealed no blood coagulation, but petechial, ecchymotic, and free hemorrhages were observed in most organs, including large ecchymotic hemorrhages on the peritoneal rumen surface. Each kidney was enveloped by a bloody gelatinous mass. In a second feeding trial to determine whether vitamins K1 and K3 were antidotal, oral administration of large quantities of vitamin K1 reduced the elevated prothrombin time; vitamin K3 acted less consistently. No trichothecene mycotoxins were found in the hay.

Based on warnings regarding use of natural sources of coumarin and dicoumarol and their known anticoagulant properties, use of A. odoratum for flavoring is discouraged. Because coumarin is widely distributed in plants, and the FDA has banned use for flavoring purposes.Leung 1996

Clinical data

Grass pollen extracts are used as immunotherapy to treat allergic rhinitis caused by grass allergens.Kleine-Tebbe 2014 A sublingual tablet containing an allergen extract of sweet vernal, orchard, perennial rye, and Kentucky blue grass (Oralair) is FDA-approved to treat allergic rhinitis caused by grass allergens.Oralair October 2014

Dosing

There is no clinical evidence to support specific dosing recommendations. Traditional use of sweet vernal grass was only external. 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.Alm 2015

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.

In temperate areas of the world, pollen from sweet vernal grass causes allergic rhinitis, conjunctivitis, and asthma.Kleine-Tebbe 2014

Toxicology

Beyond historical references to the use of sweet vernal grass as a flavoring agent, no pharmacological or toxicological studies are available.

References

Alm T. Scented grasses in Norway—identity and uses. J Ethnobiol Ethnomed. 2015;11:83.26701261
Fernald ML. Gray's Manual of Botany. 8th ed. New York, NY: American Book Co; 1950.
Hocking GM. Dictionary of Terms in Pharmacognosy and Other Divisions of Economic Botany. Springfield, IL: Charles C. Thomas; 1955.
Kleine-Tebbe J, Davies J. Grass pollen allergens. In: Akdis CE, Agache I, eds. Global Atlas of Allergy. European Academy of Allergy and Clinical Immunology; 2014. http://www.eaaci.org/globalatlas/GlobalAtlasAllergy.pdf. Accessed July 1, 2016.
Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons; 1996.
Oralair (sweet vernal, orchard, perennial rye, timothy, and Kentucky bluegrass mixed pollens allergen extract) [prescribing information]. Lenoir, NC: Greer Laboratories Inc; October 2014.
Pritchard DG, Markson LM, Brush PJ, Sawtell JA, Bloxham PA. Haemorrhagic syndrome of cattle associated with the feeding of sweet vernal (Anthoxanthum odoratum) hay containing dicoumarol. Vet Rec. 1983;113(4):78-84.6194608

Disclaimer

This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

Further information

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