Narrated Hudhaifa':
The Prophet and I walked till we reached the dumps of some people. He stood, as any one of you stands, behind a wall and urinated. I went away, but he beckoned me to come. So I approached him and...
O Allah, praise is to You. You have clothed me. I ask You for its goodness and the goodness of what it has been made for, and I seek Your protection from the evil of it and the evil of what it has been made for.
Info: Abu Dawud and At-Tirmidhi. See also Al-Albani, Mukhtasar Shamd'il At-Tirmidhi, p. 47.