Flowering shoot tips forms the medicinal part.
Yarrow chemical composition
It contains 0.13-1 % essential oil. Proazolens are present in this genus. Achillicin was the first proazolen extracted from the millefoilum species. betonicine, L-(-) stachydrine, betaine, a C base, gulucoside of luteolin, gulucoside of apigenin and free Apigenin are also found in this plant.
The active ingredient of yarrow are diacetyl matricarin, matricarin and two sesquiterpene lactones.