Mishkat al-Masabih 4573
Nafi' said Ibn ‘Umar told him he was suffering from blood pressure and asked him to bring him a cupper, telling him to be sure to bring a young man and see that he brought neither an old man nor a boy. And Ibn ‘Umar said he had heard God’s messenger say:
“Cupping before food is best; it increases the intelligence, increases the memory and increases the memory of one who has a good memory. He who has himself cupped should choose Thursday, doing it in the name of God most high; but avoid cupping on Friday, Saturday and Sunday. Get yourselves cupped on Monday and Tuesday, but avoid cupping on Wednesday for it is the day when Job was smitten with affliction. Tubercular leprosy and leprosy make their appearance only on Wednesday or Tuesday night.” 

Ibn Majah transmitted it.
وَعَن نافعٍ قَالَ: قَالَ ابنُ عمر: يَا نَافِع يَنْبغ بِي الدَّمُ فَأْتِنِي بِحَجَّامٍ وَاجْعَلْهُ شَابًّا وَلَا تَجْعَلهُ شَيخا وَلَا صَبيا. وَقَالَ ابْنِ عُمَرُ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «الْحِجَامَةُ عَلَى الرِّيقِ أَمْثَلُ وَهِيَ تُزِيدُ فِي الْعَقْلِ وَتُزِيدُ فِي الْحِفْظِ وَتُزِيدُ الْحَافِظَ حِفْظًا فَمَنْ كَانَ مُحْتَجِمًا فَيَوْمَ الْخَمِيسِ عَلَى اسْمِ اللَّهِ تَعَالَى وَاجْتَنِبُوا الْحِجَامَةَ يَوْمَ الْجُمُعَةِ وَيَوْمَ السَّبْتِ وَيَوْمَ الْأَحَدِ فَاحْتَجِمُوا يَوْمَ الِاثْنَيْنِ وَيَوْمَ الثُّلَاثَاءِ وَاجْتَنِبُوا الْحِجَامَةَ يَوْمَ الْأَرْبِعَاءِ فَإِنَّهُ الْيَوْمُ الَّذِي أُصِيبَ بِهِ أَيُّوبُ فِي الْبَلَاءِ. وَمَا يَبْدُو جُذَامٌ وَلَا بَرَصٌ إِلَّا فِي يَوْمِ الْأَرْبِعَاءِ أَوْ لَيْلَةِ الأربعاءِ» . رَوَاهُ ابنُ مَاجَه