Escin may reduce inflammation and oedema by acting as a steroid - without the side effects of steroids. This paper states “the anti-inflammatory effects of escin were related to down-regulation of pro-inflammatory mediators (ie, PGE2, TNF-α, and IL-1β), through the increased expression of the glucocorticoid receptor”. In plain English this means that the horse chestnut extract escin (and most probably its chemical cousin esculin, which has similar activity) acts on the same receptor that corticosteroids act.