Hadithcore
Mishkat al-Masabih, 4538

Abud Darda’ reported God's messenger as saying, “God has sent down both the disease and the cure, and He has appointed a cure for every disease, so treat yourselves medically, but use nothing unlawful.” Abu Dawud transmitted it.

وشطره الأول (صَحِيحٌ) وَعَنْ أَبِي الدَّرْدَاءِ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِنَّ اللَّهَ أَنْزَلَ الدَّاءَ وَالدَّوَاءَ وَجَعَلَ لِكُلِّ دَاءٍ دَوَاءً فَتَدَاوُوا وَلَا تداوَوْا بحرامٍ» . رَوَاهُ أَبُو دَاوُد

References1 variant
In-Book Reference
Book 23, Hadith 25