Al-Tirmidhi (7) narrated that ‘Aa’ishah said:
When the Prophet (peace and blessings of Allaah be upon him) exited the toilet, he used to say Ghufraanaka (Your forgiveness).
The scholars have stated that the reason why one should seek forgiveness when exiting the toilet is that it is for not remembering Allaah whilst one was in the toilet. The Muslim regards that as a shortcoming and makes up for it by asking for forgiveness.
See al-Nihaayah fi Ghareeb al-Hadeeth by Ibn al-Atheer (3/703).
Memorize,put the Dua into practice and share with Family and Friends.