The Prophet (sal Allaahu alayhi wa sallam) said: When any one of you urinates, he must not touch his penis with his right hand, and when he goes to relieve himself he must not wipe himself with his right hand (in the privy), and when he drinks, he must not drink in one breath.  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا بَالَ أَحَدُكُمْ فَلاَ يَمَسَّ ذَكَرَهُ بِيَمِينِهِ وَإِذَا أَتَى الْخَلاَءَ فَلاَ يَتَمَسَّحْ بِيَمِينِهِ وَإِذَا شَرِبَ فَلاَ يَشْرَبْ نَفَسًا وَاحِدًا  

The Prophet ﷺ used his right hand for taking his food and drink and used his left hand for other purposes.  

حَدَّثَتْنِي حَفْصَةُ زَوْجُ النَّبِيِّ ﷺ أَنَّ النَّبِيَّ ﷺ كَانَ يَجْعَلُ يَمِينَهُ لِطَعَامِهِ وَشَرَابِهِ وَثِيَابِهِ وَيَجْعَلُ شِمَالَهُ لِمَا سِوَى ذَلِكَ  

The Prophet ﷺ used his right hand for getting water for ablution and taking food, and his left hand for his evacuation and for anything repugnant.  

كَانَتْ يَدُ رَسُولِ اللَّهِ ﷺ الْيُمْنَى لِطُهُورِهِ وَطَعَامِهِ وَكَانَتْ يَدُهُ الْيُسْرَى لِخَلاَئِهِ وَمَا كَانَ مِنْ أَذًى  

Aishah, also reported a tradition bearing similar meaning through another chain of transmitters.  

عَنِ النَّبِيِّ ﷺ بِمَعْنَاهُ