Yarrow, according to American Indian lore and traditional herbal remedies, has long been a natural remedy for head colds, eczema and slowing blood flow. Yarrow's ability to staunch blood flow gives it the additional names "bloodwort" and "nosebleed." Those with excessive menstrual flow may even sip yarrow tea to ease the bleeding. Though yarrow is perfectly safe in small quantities, its cousin, poison hemlock, masquerades as yarrow and can kill a human very quickly. If foraging for your own herbs, carefully note the differences to avoid poisoning yourself.
Examine your wild plants reference guide carefully, copying the pages with pictures of hemlock and yarrow. "Peterson's Guide to Edible Wild Plants" has clear colour pictures for reference.
Lay the pictures side by side for comparison. Circle the flowers with a red paint pen; other pens won't show up as well. Label the yarrow flowers as tightly clustered and slightly larger than the hemlock flowers. Hemlock flowers are spaced farther apart and are smaller.
Circle the leaves on each plant. Label the yarrow leaves as "good" and the hemlock leaves as "poison." Label each plant with its name, as well. Careful labelling will help you keep track of which plant is which and avoid mistakes.
Note that yarrow leaves have thin, delicate, feathery lobes. Yarrow leaves are much smaller than hemlock leaves and are softer. Hemlock leaves are broad in the centre with flat, spiky lobes projecting from the sides.
Dry and steep yarrow leaves as a tea. Sweeten them with honey to counteract the slightly bitter taste. If you have a dog or horse with you, watch it carefully. Nonhuman mammals will avoid poison hemlock at all costs. If your animal won't touch it, neither should you.
Consult with a doctor before taking any herbal remedy. Yarrow may lighten menstrual flow or stop it altogether. Pregnant women should never drink yarrow.