Sweet clover

Information
Application
Notes
References

Photo: Sertürner Bildarchiv

Botanical name

Melilotus officinalis (L.) Lam.

Family

Fabaceae

Common name

Yellow sweet clover, Yellow melilot, Ribbed melilot, Yellow blossom, Sweet leaf clover

Information about the plant

Sweet clover is widely distributed throughout Europe and Asia, where it grows along paths and around fields. The genus name Melilotus comes from the Greek ‘meli’ (= honey) and ‘lotos’ (= clover in the broad sense). In fact, the numerous fragrant, bright yellow flowers make an excellent pasture for honeybees. The specific epithet officinalis suggests that it is an old medicinal plant, as the "officina" is the sales room of a pharmacy and ‘officinalis’ means commonly used in the pharmacy. Its preferred habitats are rocky roadsides and field margins, and its trifoliate leaves are very characteristic.

Sweet clover grows to almost 1 m tall. The long stems bear trifoliate leaves with obovate, irregular, and slightly toothed leaflets. The small yellow, butterfly-shaped flowers are arranged in one-sided racemes, with 30 to 70 flowers per raceme. Their wings are larger than the keel. When the fruit ripens, the light-brown rounded pods form. The flowering time is from May to September.

Medicinally used parts of plants (herbal drug)

The dried herb (Meliloti herba) harvested during the flowering season is used. Enzymatic processes during drying produce the volatile coumarin, which gives the herb its characteristic odor.

Constituents of the herbal drug

Sweet clover contains coumarin, melilotoside, flavonoids, and saponins.

Quality of the drug

The quality of the sweet clover herb (Meliloti herba) is specified in the European Pharmacopoeia (Ph. Eur.).

Medical applications

Recognised medical use

The HMPC has classified a sweet clover as a traditional herbal medicinal product (see ‘Traditional use’).

ESCOP: For internal use to treat symptoms of chronic venous insufficiency (CVI), such as pain and a feeling of heaviness in the legs, night-time calf cramps, itching, and swelling.

Traditional use

Sweet clover has been classified by the HMPC as a traditional herbal medicinal product (Article 16a of Directive 2001/83/EC). Based upon long-standing use, sweet clover may be used internally to alleviate symptoms associated with mild venous circulatory disorders, such as a feeling of heaviness in the legs. Externally, it may be used to treat mild skin inflammation.

Herbal drug preparations in finished dosage forms

Chopped sweet clover for tea preparation
Fluid extract in liquids
Dry extracts in tablets and capsules
Melilotus officinalis homeopathic mother tincture in drops and other liquids

Dosage

Finished medicinal products: See patient information leaflet.

Tea: Drinking sweet clover tea is not recommended due to the variable coumarin content in the herb (see notes).

Preparation of a tea

Not applicable.

Notes

Patients with a history of liver disease should not take sweet clover.

Coumarin has been shown to be hepatotoxic in various animal species. However, the assumption that it has mutagenic, genotoxic, and carcinogenic effects has not been confirmed. The tolerable daily intake (TDI) is 0.1 mg/kg body weight (Federal Institute for Risk Assessment).