Al-Kāfi - Volume 6 > The Leek
Hadith #6

عَنْهُ عَنْ دَاوُدَ بْنِ أَبِي دَاوُدَ عَنْ رَجُلٍ رَأَى أَبَا الْحَسَنِ ( عليه السلام ) بِخُرَاسَانَ يَأْكُلُ الْكُرَّاثَ مِنَ الْبُسْتَانِ كَمَا هُوَ فَقِيلَ لَهُ إِنَّ فِيهِ السَّمَادَ فَقَالَ ( عليه السلام ) لَا تَعَلَّقُ بِهِ مِنْهُ شَيْ‏ءٌ وَ هُوَ جَيِّدٌ لِلْبَوَاسِيرِ .

6. It is narrated from the narrator of the previous Hadith from Dawud ibn abu Dawud who has said the following: “A man had seen abu al-Hassan, ‘Alayhi al-Salam, in Khurasan eating leeks from the garden as it was and it was said to him (the Imam), ‘There is fertilizer with it.’ He (the Imam) said, ‘It does not stick to it and it is very good for hemorrhoids.’”