Extract for which there is little research showing it to have any benefit for skin. What studies do exist were performed in vitro, and indicate that it may have anti-inflammatory properties (Sources: Planta Medica, 1991, volume 57, pages 444–446, and 1994, volume 60, pages 37–40). However, yarrow also has properties that may cause skin irritation and photosensitivity (Source: Healthnotes Review of Complementary and Integrative Medicine, www.healthwell.com/healthnotes/herb).
http://www.paulaschoice.com/cosmetic-ingredient-dictionary/definition/yarrow-extract