Medically reviewed on Jun 7, 2018
What is Red Clover?
This perennial herb is commonly found in light, sandy soil in meadows throughout Europe and Asia. It is naturalized in North America, where its nitrogen-fixing properties are used in pasture renovation. Dense terminal heads with up to 125 fragrant flowers are borne at the end of the branched stems. The flowers range from magenta to white in color and are butterfly shaped. The leaves are in groups of 3 ovate leaflets, often notched at the tip, with a characteristic lighter water mark on their upper surface.
Red clover also is known as cow clover, creeping clover, meadow clover, purple clover, trefoil, and Flos Trifolii.
What is it used for?
Dried red clover flowers have been used in traditional medicine to treat a wide variety of ailments, including jaundice, cancer, breast tissue infections, joint disorders, and respiratory conditions (eg, whooping cough, bronchial asthma), and as a sedative. The plant was thought to purify the blood by promoting urine and mucus production, improving circulation, and stimulating secretion of bile. Red clover ointments have been used topically to speed wound healing and to treat psoriasis, eczema, and rashes. Respiratory complaints have been treated with an infusion; poultices of the whole plant have been used as topical applications for cancerous growths.
There is no clinical evidence to support any of these uses or for use in menopause-related conditions. Safety of use in treating breast cancer has not been determined, and protection against prostate cancer has not yet been confirmed by clinical trials.
What is the recommended dosage?
Red clover blossoms for sedation were formerly used at doses of 4 g, but are now used primarily as a source of isoflavones, plant substances that can have healing effects. The usual dose is 40 to 80 mg/day of standardized isoflavones. Several commercial preparations are available.
Red clover should not be used by patients with hormonal disorders or estrogen-dependent breast cancer (or risk of), or during pregnancy or lactation. Red clover supplementation is not advised in children younger than 12 years.
Isoflavonoids may interfere with hormonal agents; avoid use with oral contraceptives, estrogen, or progesterone therapies, and use cautiously with tamoxifen or letrozole.
Few adverse reactions have been reported in doses used in clinical trials. High doses of isoflavones have been associated with loss of appetite, swelling of the ankles and feet, and abdominal tenderness.
The phytoestrogens (plant-based estrogens) in red clover may be associated with a risk of adverse effects, including increased incidence of endometrial, ovarian, and breast cancers.