Couch grass is stated to possess diuretic properties due to the presence of carbohydrates such as mannitol and inulin. It has been traditionally used for urinary tract infections and conditions relating to the kidneys, such as kidney stones. The essential oil has been used for its antimicrobial effects, while the extracts of couch grass have been used as a dietary component in patients with diabetes. There is no formal clinical data available, however, to support these claims. Literature on couch grass is primarily in journals on botany and genomics.
Couch grass is listed by the Council of Europe as a natural source of food flavoring. In the United States, it is listed as GRAS (Generally Recognized as Safe).
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
* Key to grades
A: Strong scientific evidence for this use B: Good scientific evidence for this use C: Unclear scientific evidence for this use D: Fair scientific evidence for this use (it may not work) F: Strong scientific evidence against this use (it likley does not work)
Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
There is no proven safe or effective dose for couch grass in adults. Traditionally, 4-8 grams of dried rhizome has been taken three times daily. As a liquid (1:1 in 25% alcohol) extract, 4-8 milliliters three times per day has been used. As a tincture (1:5 in 40% alcohol), 5-15 milliliters three times per day has been used.
Children (younger than 18 years):
There is no proven safe or effective dose for couch grass in children.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Avoid in individuals with a known allergy or hypersensitivity to any constituent of couch grass, or to other members of the Poaceae/Gramineae family. Inulin may trigger an allergic reaction in some individuals, which may manifest as throat swelling, nasal itching, coughing, or difficulty breathing.
Side Effects and Warnings
The safety and efficacy of couch grass has not been systematically studied for any indication in available reports. However, traditional use suggests that couch grass is generally well tolerated. Couch grass is accepted in the Indian and Colonial Addendum of the British Pharmacopoeia for use in the Australian, Eastern and North American Colonies, where it is much employed.
Excessive and prolonged use of couch grass should be avoided due to its reputed diuretic action, as this may result in hypokalemia (abnormally low potassium levels in the blood).
Caution is advised in patients who have edema (swelling) caused by heart or kidney disease. Based on tradition, couch grass should be taken with plenty of fluids to flush out the urinary tract.
Pregnancy and Breastfeeding
Couch grass is not recommended in pregnant or breastfeeding women due to lack of available scientific evidence.
Due to its mild diuretic property, couch grass may increase the risk for high blood pressure and abnormally low potassium levels in the blood. Caution is advised in patients taking other blood pressure medications due to possible additive effects.
Theoretically, couch grass may have an additive effect with other diuretic drugs.
Interactions with Herbs and Dietary Supplements
Theoretically, couch grass may increase the risk for high blood pressure and abnormally low potassium levels in the blood due to its mild diuretic effects. Caution is advised in patients taking other blood pressure altering herbs or supplements due to possible additive effects.
Theoretically, couch grass may have an additive effect with other diuretic herbs and supplements.
Ben Arye E, Goldin E, Wengrower D, et al. Wheat grass juice in the treatment of active distal ulcerative colitis: a randomized double-blind placebo-controlled trial. Scand.J Gastroenterol. 2002;37(4):444-449.
Mascolo N. Biological screening of Italian medicinal plants for anti-inflammatory activity. Phytother Res 1987;1:28-29.
Mueller RS, Bettenay SV, Tideman L. Aero-allergens in canine atopic dermatitis in southeastern Australia based on 1000 intradermal skin tests. Aust Vet.J 2000;78(6):392-399.
Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. 1996.
Weston LA, et al. Isolation, characterization and activity of phytotoxic compounds from quackgrass (Agropyron repens (L.) Beauv). J Chem Ecol 1987;13:403-421.
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.