Al-Kāfi - Volume 6 > Eating Clay
Hadith #9

عَلِيُّ بْنُ مُحَمَّدٍ عَنْ بَعْضِ أَصْحَابِنَا عَنْ جَعْفَرِ بْنِ إِبْرَاهِيمَ الْحَضْرَمِيِّ عَنْ سَعْدِ بْنِ سَعْدٍ قَالَ سَأَلْتُ أَبَا الْحَسَنِ ( عليه السلام ) عَنِ الطِّينِ فَقَالَ أَكْلُ الطِّينِ حَرَامٌ مِثْلُ الْمَيْتَةِ وَ الدَّمِ وَ لَحْمِ الْخِنْزِيرِ إِلَّا طِينَ قَبْرِ الْحُسَيْنِ ( عليه السلام ) فَإِنَّ فِيهِ شِفَاءً مِنْ كُلِّ دَاءٍ وَ أَمْناً مِنْ كُلِّ خَوْفٍ .

9. Ali ibn Muhammad has narrated from certain persons of our people from Ja‘far ibn Ibrahim al-Hadramiy from Sa‘d ibn Sa‘d who has said the following: “I once asked abu al-Hassan, ‘Alayhi al-Salam, about clay. He (the Imam) said, ‘ It is unlawful like dead animals, blood, flesh of pigs except the clay from the grave of al-Husayn, ‘Alayhi al-Salam, in which there is cure for all kinds of illness and security from all kinds of fear.”’