It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) in a marfu' form that Allah has sent down no disease except that He has also sent down its cure. Whoever knows it, knows it, and whoever remains unaware of it, remains unaware.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 3922
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد حسن.