Witch-hazel (Hamamelis) is a genus of flowering plants in the family Hamamelidaceae, with two species in North America (H. virginiana and H. vernalis), and one each in Japan (H. japonica) and China (H. mollis).
The bark and leaves are astringent; the extract, also referred to as witch hazel, is used medicinally. Extracts from its bark and leaves are used in aftershave lotions and lotions for treating bruises and insect bites. Witch hazel's medicinal components (including tannin, gallic acid, catechins, proanthocyanins, flavonoids (kaempferol, quercetin), essential oil (carvacrol, eugenol, hexenol), choline, saponins, and bitters) can be extracted by alcohol/solvent soaking or by distillation. Distilled witch hazel contains no tannins, however.
Witch hazel hydrosol (i.e. a liquid preparation) is a strong anti-oxidant and astringent, which makes it useful in treating acne. It is often used as a natural remedy for psoriasis, eczema, aftershave applications, ingrown nails, to prevent sweating of the face, cracked or blistered skin, for treating insect bites, poison ivy, and as a treatment for varicose veins and hemorrhoids. Witch hazel is also a good after-shave treatment for shaving cuts and abrasions.
Witch hazel can be used and applied in a number of ways. Some people like to wet a cotton ball with some and lightly wipe it over their face after a shave (rinsing after this is not required). Others use a small spray bottle to mist or spray the witch hazel on afterwards.
One method of using witch hazel in one's shaving regimen:
Witch hazel preparations usually contain either alcohol or parabens as a preservative. Depending on the percentage content by volume, alcohol can impart a sting to the face. Alcohol is also astringent and can multiply the astringent effects of witch hazel.