Willow trees fall under the Salix genus and include over 400 species, with two of the most well-known medicinal species being the white willow (Salix alba) and the black willow (Salix nigra).

T. parthenium and Salix alba (white willow) either alone or in combination (Mig-RL ®) were recently shown to inhibit binding to 5-HT 2A/2C receptors; T. parthenium failed to recognise 5-HT 1D ...