Witch hazel (Hamamelis virginiana) water is produced from the bark, leaves and twigs of the Witch Hazel tree. Contains tannins or astringents, it can relieve itching, pain, and swelling. Often found in toners, especially those formulated for oily skin. Serves as a skin conditioning agent, improving the appearance of dry and damaged skin.
Chem Res Toxicol. 2008 Mar;21(3):696-704. doi: 10.1021/tx700425n.