According to the Shafi'i school of Sunni Islamic jurisprudence, as systematised by Al-Nawawi in his book "Minhadj", the following things are "najis": wine and other spirituous drinks, dogs, swine, dead animals that were not ritually slaughtered, blood, excrements, and the milk of animals whose meat Muslims are not allowed to eat. Spirituous drinks are not impure according to the Hanafi school, while living swine and dogs are not impure according to the Malikis. There is a difference of opinion as to whether alcoholic drinks are "najis".