Narrated Abu Aiyub Al-Ansari: Allah's Apostle said, "If anyone of you goes to an open space for answering the call of nature he should neither face nor turn his back towards the Qibla; he should either face the east or the west."
Hadith ReferenceSahih Bukhari / The Book of Wudu (Ablution) / Hadith: 144
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة