Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever eats clay has himself helped in killing himself."
Abu Ahmad (Ibn Adi) said: I do not know anyone who narrates this from Suhayl bin Abi Salih except this Abd al-Malik, and he is majhul (unknown).
The Shaykh said: Even if this were authentic, it would not indicate prohibition; rather, there is dislike in that thing whose excess harms the body.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19719