Place three ounces of [quicklime] in a potter's vase and cook it in the manner of a porridge. Then take one ounce of orpiment and cook it again, and test it with a feather to see if it is sufficiently cooked. Take care, however, that it is not cooked too much and that it not stay too long on the skin, because it causes intense heat." This 12th-century depilatory would certainly remove your hair... and your health as well, since orpiment is sulfide of arsenic!
Source: The Trotula, edited and translated by Monica H. Green