It is narrated from Hazrat Abu Ayyub Ansari (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: When any one of you goes to relieve himself, he should neither face the Qiblah nor turn his back towards it.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 23559