Al-Kāfi - Volume 4 > The Case of a Fasting Person’s Use of Bath Room and Apply Cupping
Hadith #4

4ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ أَبِي حَمْزَةَ عَنْ أَبِي بَصِيرٍ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ السَّلاَم) عَنِ الرَّجُلِ يَدْخُلُ الْحَمَّامَ وَهُوَ صَائِمٌ قَالَ لا بَأْسَ.

4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from al-Qasim ibn Muhammad from Ali ibn abu Hamzah from abu Basir who has said the following: “I once asked abu Ja‘far, ‘Alayhi al-Salam, about a man who uses the bathhouse when fasting. He (the Imam) said, ‘It is not harmful.’”