Achillea (Yarrow) is an important diaphoretic herb and is a standard remedy for helping the body deal with fever. It stimulates digestion and tones blood vessels. Achillea is considered a specific for thrombotic conditions associated with hypertension, and is thought to lower blood pressure through dilation of peripheral vessels. Researchers believe that its anti-inflammatory and anti-spasmodic actions are related to its content of flavonoids. Used externally, Achillea aids in wound healing." Hoffman, Medical Herbalism