It was narrated from Abu Umamah that:
The Messenger of Allah said: "None of you should fail to say, when he enters his toilet: 'Allahumma inni a`udhu bika minar-rijsin-najis, al-khabithil-mukhbith, ash-Shaitanir-rajim (O Allah, I seek refuge with You from the filthy and impure, the evil one with evil companions, the accursed Shaitan).'" (Da'if)
Another chain with a slightly different wording from Ibn Abi Maryam who mentioned similar, but he did not say in his narration: "Minar-rijsin-najis (From the filthy and the impure)" he only said: "Minal-khabithil-mukhbith, ash-Shaitanir-rajim (From the evil one with evil companions, the accursed Shaitan)."