The yarrow essential oils are dark blue and contain over 15% chamazulene, which acts as a great natural colorant.
It gives the serum a light green color. Yarrow is also known as milfoil, a reference to its feathery appearance from fern-like feathery leaves.
Yarrow has a long history as a medicinal herb, which goes back to the legend of Achilles who used it for wounds inflicted during the Trojan War.