Ruscus aculeatus is an herb commonly referred to as Butcher's Broom due to its hard roots and (supposed) antibacterial properties being traditionally used to clean the cutting boards of butchers. It also holds traditional medicinal uses, which maily focus around improving blood flow in the veins by contracting them. The uses associated with this 'venotropic' action include reducing leg swelling and edema, treating chronic venous insufficiency, and treating or preventing hemhorroids.
The plant itself contains a variety of saponin structures, of which the active ones are not fully elucidated but are thought to be a collection of similar saponins known as the ruscogenins and neoruscogenins. These are present in high levels in the plant's vertical root (rhizome) and tend to be standardized for supplementation.
In regards to the plant's actions, it seems to increase the activity of noradrenaline at the level of the synapse where it contacts veins via acting through its alpha receptors.
Human evidence is limited, as while there is a large amount of evidence and a meta-analysis on a formulation of which contains this herb it is confounded by the inclusion of hesperidin methylchalcone (commonly added to venotropic agents). There are only two human studies using the herb in isolation, and the one investigating the major claim appears to support its traditional usage.
While limited evidence suggests it is effective, advocacy of the supplement is in part limited by a lack of replication with the herb in isolation as well as insufficient safety testing in humans.