وَعَن أبي كَبْشَة الْأَنْمَارِيِّ
أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ احْتَجَمَ عَلَى هَامَتِهِ مِنَ الشَّاةِ الْمَسْمُومَةِ قَالَ مَعْمَرٌ: فَاحْتَجَمْتُ أَنَا مِنْ غَيْرِ سُمٍّ كَذَلِكَ فِي يَافُوخِي فَذَهَبَ حُسْنُ الْحِفْظِ عَنِّي حَتَّى كُنْتُ أُلَقَّنُ فَاتِحَةَ الْكِتَابِ فِي الصَّلَاةِ
I had myself cupped like that in the middle of my head for a reason other than poison and suffered some loss of memory till I was recommended to use Fatihat al-Kitab in the prayer. Razin transmitted it. * An attempt was made to poison the Prophet (sallallahu alayhi wa sallam) after the conquest of Khaibar in 7 A.H., but when he had taken a mouthful of the poisoned meat he spat it out realizing that it was poisoned.
Mishkat al-Masabih 4377, Book 24, Medicine and Spells, Hadith 57. 1 min read