The Prophet ﷺ said, "If somebody takes some ʿAjwa dates every morning, he will not be affected by poison or magic on that day till night." (Another narrator said seven dates).  

قَالَ النَّبِيُّ ﷺ مَنِ اصْطَبَحَ كُلَّ يَوْمٍ تَمَرَاتٍ عَجْوَةً لَمْ يَضُرُّهُ سَمٌّ وَلاَ سِحْرٌ ذَلِكَ الْيَوْمَ إِلَى اللَّيْلِ وَقَالَ غَيْرُهُ سَبْعَ تَمَرَاتٍ  

I heard Messenger of Allah ﷺ saying, "If someone takes seven ʿajwah dates in the morning, neither magic nor poison will hurt him that day."  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ: «مَنْ تَصَبَّحَ سَبْعَ تَمَرَاتٍ عَجْوَةً لَمْ يَضُرُّهُ ذَلِكَ الْيَوْمَ سَمٌّ وَلاَ سِحْرٌ۔»