It is narrated from Sayyiduna Saeed bin Zaid (may Allah be pleased with him) that once the Messenger of Allah (peace and blessings be upon him) came to us and there was a truffle in his blessed hand. He (peace and blessings be upon him) said: "Do you know what this is? This is a truffle. The truffle is also related to «مَنّ» (which was sent down upon the Children of Israel), and its water is a cure for the eyes."