1. Touching a person of the other sex skin to skin.
2. Bleeding from any part of the body other than that which comes from the private parts.
3. Vomit, regardless of its amount.
4. Doubting whether one’s ablution has been invalidated.
5. Loud laughter during the prayer (this invalidates the prayer but not the wudhu).
6. Washing a dead person to prepare him for burial.