Achillea ptarmica, the sneezewort, sneezeweed, bastard pellitory, European pellitory, fair-maid-of-France, goose tongue, sneezewort yarrow, wild pellitory, or white tansy, is a European species of herbaceous perennial flowering plant in the genus Achillea. It is widespread across most of Europe and naturalized in scattered places in North America.
Achillea ptarmica has loose clusters of showy white, flower heads that bloom from June to August. Its dark green leaves have finely toothed margins. Like many other plants, the sneezewort's pattern of development displays the Fibonacci sequence.
The name ptarmica comes from the Greek word ptairo (=sneeze) and means 'causes sneezing'.