Najasaat means the thing which is unclean in itself, and makes other things unclean by contact. There are 10 Najasaat:-
    1. and 2. Urine and Stool
    The Urine and Stool of the following living beings are impure:
    1. Human Beings
    2. The animal, whose meat is Haram to eat, and whose blood gushes when it's great artery is cut.
    3. An animal which eats excretion
    4. A sheep which has been nursed by a she pig
    5. An animal with which a human being has had a sexual intercourse.

    3. Semen
    The semen of human beings and of every animal whose blood gushes when its great artery is cut, is impure.

    4. Dead Body
    The dead body of a human being is impure. Similarly the dead body of an animal whose blood gushes while slaughtering is impure if it dies a natural death or is killed in a manner other than that prescribed by religious law. As the blood of a fish does not gush, its dead body is pure, even if it dies in water.

    Those parts of a dead body (whether of a human being or of an animal) are pure which do not posses life in it like nails, teeth, hair, bones, horns etc.

    5. Blood
    The blood of a human being and of every animal whose blood gushes when its great artery is cut is impure. The blood of a fish or a mosquito is pure because it does not gush.

    6. and 7. Dogs and Pigs
    The dogs and pigs which live on land are impure and even their hair, bones, paws and every liquid substance of their body is impure. However, aquatic dogs and pigs are pure.

    8. Kafir
    A kafir is a person who denies Allah or the Day of Judgment, or associates anyone else with Allah, is impure. As for the people of the Scriptures (Jews and Christians) who do not accept and believe in Prophet Muhammed (peace be on him and his progeny) they are known to be impure.

    9. Alcoholic Liquor
    All Alcoholic liquors and beverages which intoxicate a person, are najis.

    10. Beer (Fuqqa)
    Sweat of an animal who persistently eats najasat is najis.