Scotch Broom (Cytisus scoparius) has a history of use in traditional European herbal medicine for circulatory problems, including varicose veins. However, its use for this indication is supported by some scientific evidence, albeit limited in quality and quantity. The primary active constituents thought to be responsible for its vascular effects are alkaloids such as sparteine, as well as flavonoids like scoparin and genistein. These compounds are believed to have vasoconstrictive and venotonic properties—meaning they can constrict blood vessels and improve vein tone, potentially reducing symptoms associated with varicose veins such as swelling and discomfort.

Some small clinical studies and pharmacological investigations have shown that extracts of Scotch Broom can increase venous tone and reduce capillary permeability, which may help prevent fluid leakage and edema. These findings are supported by several older European pharmacopeias and herbal monographs, notably the German Commission E, which approved Scotch Broom herb for supportive treatment of chronic venous insufficiency, though with caution due to potential side effects and toxicity.

However, modern large-scale clinical trials are lacking, and concerns about toxicity (especially due to sparteine) have limited its widespread clinical use. Most modern recommendations focus on safer alternatives, such as horse chestnut seed extract. In summary, there is some scientific validation for the use of Scotch Broom in treating varicose veins, but the evidence is limited (rating: 2/5), and safety concerns restrict its use.