Once upon a time, in a land called Greece, a sea nymph named Thetis married a mortal king named Peleus. In some versions of the story, that she was not a mortal woman was a deeply kept secret. In others, it was widely known.

Secret or not, Thetis wished to confer immortality on her newborn son, who, being half mortal, did not inherit his mother’s guaranteed immortality. She made a brew to make him invulnerable, and, holding the baby by one heel, dipped him in the brew.

Where his skin touched the brew, no spear or arrow could pierce it. But because Thetis had covered one of his heels with her hand, that heel remained penetrable. The boy, Achilles, grew up to be a great warrior and hero of the Trojan war. His skin served as natural armor. Only when he caught an arrow in his still vulnerable heel, was he killed.

The brew was made of yarrow. Achillea millefolium.

We are not immortal sea nymphs, and not even a bath of yarrow could make us as invulnerable as Achilles. But the story does tell us what yarrow’s medicinal property is. Physically and spiritually, yarrow is boundary medicine. 

If you see yarrow growing wild or in a garden, observe how it spreads itself everywhere, among all the other plants, but it does not invade. It leaves other plants enough room to exist. Yarrow is close friends with other plants, but its motto is, “However close we are, I’m still me and you’re still you.”

In spirit dose or flower essence, yarrow is good medicine for people who need to hold boundaries in relationships to others, while still keeping an open heart to the other person(s). In short, everyone. It is especially important, though, when holding boundaries is challenged, or when differentiating between yourself and the other person is a necessary but difficult task. For parents struggling to let their adolescent children go (and the adolescent children, too), for practitioners, who always need to maintain good boundaries with their clients, for couples, to remind them to keep their individuality within the relationship, for people dealing with codependency, for people who have difficulty saying no in general, for people who tend to regard others as more powerful than themselves, yarrow is good medicine.

Yarrow is one of the flowers traditionally used in wedding bouquets. Its medicine of being together but still individual reflects the ideal of marriage, as expressed by Khalil Gibran: “But let there be spaces in your togetherness. And let the winds of heaven dance between you. Love one another, but make not a bond of love. Let it rather be a moving sea between the shores of your souls.”

Yarrow is also good when boundaries are needed within yourself. For people recovering from addiction, yarrow’s spirit medicine can help provide boundaries against returning to the addictive patterns. For those who easily take on psychic energies, or who are doing spirit world work, yarrow also helps keep you present in yourself and not get overwhelmed.

As physical medicine, yarrow’s property also includes boundary protection. It is antiseptic and stops bleeding. As quick first aid for a cut, yarrow leaves can be chewed to a poultice and placed on the wound. It also has a long history of being used in midwifery to ease abnormally heavy menstrual or postpartum bleeding, and PMS. An old saying goes, “Yarrow grows where blood has been shed.”

Yarrow is also an aid to the liver, as are all bitter herbs, which in turn helps relieve many skin problems and digestive problems (frequently, skin or digestive problems are related to stagnation in the liver). Externally, as a salve, either on its own or combined with chamomile and/or calendula, it treats rashes, bacterial skin infections, and fungal infections. Having an affinity for the bladder and urinary tract, it is one of the herbs to use for infections there.

While yarrow comes in several different colors, white yarrow is the best to use for physical medicine. Other colors are not as strong in medicinal properties. They may be used as flower essences, although they may have slightly different effects from white yarrow. If you have access to essences from multiple colors of yarrow, try them and see what, if any, differences you notice.