Bulugh al-Maram, Book 5, Hadith 667 (In-Book) ⓘ

Anas (RAA) narrated, ‘The first time cupping was dis-liked for the one who is fasting was when Ja’far bin Abi Talib had himself cupped while fasting and the Messenger of Allah came across him and said, "Those two have broken their fast (meaning Ja'far and the man who was cupping him.)" But later on the Prophet allowed cupping for the one who is fasting. Anas used to have himself cupped while he was fasting. Related by Ad-Daraqutni, who regarded it as a strong hadith.

وَعَنْ أَنَسِ بْنِ مَالِكٍ ‏- رضى الله عنه ‏- قَالَ: { أَوَّلُ مَا كُرِهَتِ اَلْحِجَامَةُ لِلصَّائِمِ; أَنَّ جَعْفَرَ بْنَ أَبِي طَالِبٍ اِحْتَجَمَ وَهُوَ صَائِمٌ, فَمَرَّ بِهِ اَلنَّبِيُّ ‏- صلى الله عليه وسلم ‏-فَقَالَ: " أَفْطَرَ هَذَانِ " , ثُمَّ رَخَّصَ اَلنَّبِيُّ ‏- صلى الله عليه وسلم ‏-بَعْدُ فِي اَلْحِجَامَةِ لِلصَّائِمِ, وَكَانَ أَنَسٌ يَحْتَجِمُ وَهُوَ صَائِمٌ } رَوَاهُ اَلدَّارَقُطْنِيُّ وَقَوَّاهُ 1‏.‏ ‏1 ‏- منكر.‏ رواه الدارقطني ( 2 / 182 / 7 )‏ وقال: " كلهم ثقات، ولا أعلم له علة ".‏ قلت: وفي الأصل ذكرت جماعة ممن أنكروا الحديث أحدهم الحافظ نفسه.‏