1- Dead animals, which have not been slaughtered Islamically.
2- Blood that has flowed from an animal or a human body.
3- Pig or any part of it.
This is taken from Allah's words:
(Say (O Muhammad): "I find not in that which has been inspired to me anything forbidden to be eaten by one who wishes to eat it, unless it be Maytatah (a dead animal) or blood poured forth (by slaughtering or the like), or the flesh of swine (pork, etc.) for that surely is impure, or impious (unlawful).) (6:145).
And in His words:
(Forbidden to you (for food) are: AI-Maytatah (the dead animals -- cattle-beast not slaughtered), blood, the flesh of swine.) (5:3).
4- Dog. The Prophet (peace and blessings be upon him) said:
'If a dog eats out of a utensil, let him pour out its contents, and then wash it seven times, the first of which should be with mud.' (Muslim).
5. Human vomit, urine and excrement.
6- AI-Wadi (prostatic fluid emitted subsequent to urination).
7- AI-Madthi (prostatic fluid emitted as a result of sexual excitement).
8- Urine and stool of animals that is not permissible for consumption.
9- Animals that eat the feces of other animals. This is called 'aI-Jal'laalah '. Ibn Abbas (may Allah be pleased with him) said:
'The Messenger of Allah (peace and blessings be upon him) forbade drinking the milk of the Jal'laalah'. (Abu Dawood)
Question: Is a non-Muslim filthy, such that a Muslim must redo his wudhu if he touches one of them?
The preponderant opinion is that a non-Muslim is not filthy in this sense, for the Messenger of Allah (peace and blessings be upon him) ate from the gifts given to him by non-Muslims; although a non-Muslim is filthy in matters pertaining to Aqeedah (Creedal Beliefs).