Sunan Ibn Majah, Book 1, Hadith 566 (In-Book) ⓘ

It was narrated that Umm Qais bint Mihsan said: "I came to the Messenger of Allah with a son of mine who was not yet eating solid food, and he (the baby) urinated on him. He called for water and sprinkled it over (the urine)."

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَمُحَمَّدُ بْنُ الصَّبَّاحِ، قَالاَ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنْ أُمِّ قَيْسٍ بِنْتِ مِحْصَنٍ، قَالَتْ دَخَلْتُ بِابْنٍ لِي عَلَى رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ لَمْ يَأْكُلِ الطَّعَامَ فَبَالَ عَلَيْهِ فَدَعَا بِمَاءٍ فَرَشَّ عَلَيْهِ ‏.‏