Sweet clover, long popular as food for grazing animals, is used medicinally as well. It contains various substances in the coumarin family. These chemicals are thought to help strengthen the walls of blood and lymph vessels. However there is no more than preliminary evidence that sweet clover is effective for any medical condition. In addition, use of sweet clover presents some safety concerns. (See Safety Issues for more information.)

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Sweet Clover and Its History  

The name Melilotus originates from the Greek word for honey, meli , and a term for clover-like plants, lotos . There are four common species in this genus of Eurasian origins: Melilotus alba , M. indica , M. officinalis , and M. altissimus .

The fresh or dried leaves and flowering stems of sweet clover were traditionally used as a diuretic.

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What Is Sweet Clover Used for Today?  

Germany's Commission E has authorized use of sweet clover extract for symptoms of venous insufficiency (a condition closely related to varicose veins) as well as for the treatment of phlebitis and hemorrhoids . 1 When used for this purpose, however, sweet clover is generally combined with bioflavonoids such as oxerutin . However, there is no meaningful evidence as ytet that sweet clover taken alone is effective for these conditions.

Sweet clover contains coumarins, substances related to the prescription blood-thinner warfarin . Most scientific study relevant to sweet clover involves prescription drugs that combine coumarins and bioflavonoids. These medications have also been used to treat venous insufficiency, as well as numerous other conditions, including elephantiasis, hemorrhoids, mild digestive disturbances and various forms of edema . 2-7 However, it isn't clear whether sweet clover extracts containing coumarins would work in the same way as the coumarin portion of these pharmaceutical products.

Topical treatments made from sweet clover are sometimes recommended for the treatment of hemorrhoids and minor injuries , 9 but as yet there is no real scientific evidence to support these proposed uses.

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Dosage  

Sweet clover products are standardized to their coumarin content. For treating symptoms of venous insufficiency/ varicose veins, a daily dosage of a sweet clover preparation or extract providing 3 to 30 mg of coumarin is taken internally. 8 (See "Safety Issues," below.)

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Safety Issues  

The safety of any medicinal use of sweet clover has not been established in humans. Sweet clover contains various substances in the coumarin family. Many (but not all) of these substances thin the blood, and might cause excessive bleeding in some individuals. In particular, sweet clover should not be combined with blood-thinning drugs such as warfarin (Coumadin), heparin or drugs in the aspirin family.

Safety in pregnant or nursing women, young children, or individuals with severe liver or kidney disease has not been established.

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Interactions You Should Know About  

If you are taking blood-thinning drugs such as warfarin (Coumadin), heparin , clopidogrel (Plavix), pentoxifylline (Trental ) or drugs in the aspirin family, you should not use sweet clover.