Sahih al-Bukhari 5708
صحيح البخاري#5708SahihNarrated Sa`id bin Zaid:I heard the Prophet (ﷺ) saying, "Truffles are like Manna (i.e. they grow naturally without man's care) and their water heals eye diseases
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 76:28