Praise be to Allaah.
Touching dogs or their saliva does not nullify
wudoo because if tahaarah is done according to the rules of shareeah, nothing
can nullify it except things for which there is evidence in shareeah. There is no
such evidence that touching dogs or their saliva have this effect. It was not mentioned by
the scholars among the things that nullify wudoo.
Ibn Qudaamah mentioned in al-Mughni (1/264) things that nullify
wudoo, and he did not mention touching dogs or their saliva. Then he said:
These are all the things that nullify tahaarah, and it cannot be nullified by
anything else according to the view of the majority of scholars
But there is no doubt that dogs saliva is very dirty and
extremely naajis (impure), and it can only be removed by washing seven times, one of them
with earth. There is a difference between this and something which nullifies tahaarah. And
Allaah knows best.