Narrated `Ali: I used to get the emotional urethral discharge frequently so I requested Al-Miqdad to ask the Prophet about it. Al-Miqdad asked him and he replied, "One has to perform ablution (after it)." (See Hadith No. 269).
Hadith ReferenceSahih Bukhari / The Book of Knowledge / Hadith: 132
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة