"And We shaded with clouds and sent down on you Al-Manna and the quail,... (up to) wronged themselves." (V.2:57)

Sahih al-Bukhari · Book 65 · Hadith 4478

حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا سُفْيَانُ، عَنْ عَبْدِ الْمَلِكِ، عَنْ عَمْرِو بْنِ حُرَيْثٍ، عَنْ سَعِيدِ بْنِ زَيْدٍ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ الْكَمْأَةُ مِنَ الْمَنِّ، وَمَاؤُهَا شِفَاءٌ لِلْعَيْنِ ‏"‏‏.‏

Narrated Sa`id bin Zaid: Allah's Messenger (ﷺ) said, "The Kam'a (i.e. a kind of edible fungus) is like the Manna (in that it is obtained without effort) and its water is a (medicine) cure for eye trouble."