Give him honey. So he gave him that and then came and said: I gave him honey but it has only made his bowels more loose. He said this three times; and then he came the fourth time, and he (the Holy Prophet) said: Give him honey. He said: I did give him, but it has only made his bowels more loose, whereupon Messenger of Allah ﷺ said: Allah has spoken the truth and your brother's bowels are in the wrong. So he made him drink (honey) and he was recovered.  

جَاءَ رَجُلٌ إِلَى النَّبِيِّ ﷺ فَقَالَ إِنَّ أَخِي اسْتَطْلَقَ بَطْنُهُ فَقَالَ رَسُولُ اللَّهِ ﷺ اسْقِهِ عَسَلاً فَسَقَاهُ ثُمَّ جَاءَهُ فَقَالَ إِنِّي سَقَيْتُهُ عَسَلاً فَلَمْ يَزِدْهُ إِلاَّ اسْتِطْلاَقًا فَقَالَ لَهُ ثَلاَثَ مَرَّاتٍ ثُمَّ جَاءَ الرَّابِعَةَ فَقَالَ اسْقِهِ عَسَلاً فَقَالَ لَقَدْ سَقَيْتُهُ فَلَمْ يَزِدْهُ إِلاَّ اسْتِطْلاَقًا فَقَالَ رَسُولُ اللَّهِ ﷺ صَدَقَ اللَّهُ وَكَذَبَ بَطْنُ أَخِيكَ فَسَقَاهُ فَبَرَأَ  

This hadith has been narrated on the authority of Abu Sa'id Khudri through another chain of transmitters but with a slight variation of wording.  

أَنَّ رَجُلاً أَتَى النَّبِيَّ ﷺ فَقَالَ إِنَّ أَخِي عَرِبَ بَطْنُهُ فَقَالَ لَهُ اسْقِهِ عَسَلاً بِمَعْنَى حَدِيثِ شُعْبَةَ