Musnad Ahmad 30:3205

Muhammad ibn Ja'far narrated to us, he said: Shu'bah narrated to us, from Abu Bishr, from Shahr ibn Hawshab, from Abu Hurairah, from the Prophet, may Allah bless him and grant him peace, that he said: "The truffle is of the manna, and its water is a cure for the eye. And the 'ajwah (date) is from Paradise, and it is a cure for poison."