Estrovera contains a special extract of rhubarb root (ERr 731) that has been shown in clinical studies to significantly reduce menopausal hot flashes compared to placebo. Product Review as Follows: From Virginia: "Estrovera was recommended by my physician to try to soothe hot flashes during the perimenopausal phase. Although the hot flashes have not completely ceased, I believe the Estrovera has helped..."