Witch Hazel is an astringent produced from the leaves and bark of the North American shrub Witch-hazel. Witch Hazel is mainly used externally on sores, bruises and swelling. The main constituents of the extract include tannin, gallic acid, catechins, proanthocyanins, flavonoids (kaempferol, quercitin), essential oil (carvacol, eugenol, hexaenol), choline, saponins, and bitters. Distilled Witch Hazel sold in drug stores and pharmacies supposedly contains no tannin.
Actually there is no essential oil of Witch Hazel being produced. The plant doesn't produce enough essential oil to make production viable. However there are various distillates of Witch hazel (called Hydrosols or Hydrolats) that are gentler than the "drug store" Witch Hazel which contains alcohol.
Uses of Witch hazel
Witch hazel Hydrosol is used in skincare, is highly anti-oxidant and astringent. It has been recommended for for psoriasis, eczema, cracked or blistered skin, for treating insect bites, and as the treatment of choice for varicose veins and hemorrhoids.
It is also an active ingredient in some eye-drop medications like Optrex .