Ata' bin al-Sa'ib narrates: I came to Abu Abd al-Rahman, and he was cauterising a boy. I asked: "Are you cauterising him?" He replied: "Yes, it is the remedy of the Arabs. Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrated that the Prophet (peace and blessings be upon him) said: 'Indeed, Allah Almighty has not sent down any disease without also sending down a remedy for it; whoever is ignorant of it remains ignorant of it, and whoever knows it knows it.'"
Imam Ahmad recorded it. Ata' suffered from mental confusion (ikhtilat) late in life, and the rest of its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطب / 8375