كتاب الحيض
3
The Book of Menstruation
(32)
Chapter: What should be said when entering the area in which one relieves himself
(32)
باب مَا يَقُولُ إِذَا أَرَادَ دُخُولَ الْخَلاَءِ ‏
Sahih Muslim 375 b

This hadith is also transmitted by 'Abd al-'Aziz with the same chain of transmitters, and the words are:

I seek refuge with Allah from the wicked and noxious things.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالاَ حَدَّثَنَا إِسْمَاعِيلُ، - وَهُوَ ابْنُ عُلَيَّةَ - عَنْ عَبْدِ الْعَزِيزِ، بِهَذَا الإِسْنَادِ وَقَالَ ‏ "‏ أَعُوذُ بِاللَّهِ مِنَ الْخُبْثِ وَالْخَبَائِثِ ‏"‏ ‏.‏
Reference : Sahih Muslim 375 b
In-book reference : Book 3, Hadith 153
USC-MSA web (English) reference : Book 3, Hadith 730
  (deprecated numbering scheme)