Mishkat al-Masabih 23 Medicine and Spells كتاب الطب والرقى 19

عَنْ أُسَامَةَ بْنِ شَرِيكٍ قَالَ: قَالُوا: يَا رَسُول الله أفنتداوى؟ قَالَ: «نعم يَا عبد اللَّهِ تَدَاوَوْا فَإِنَّ اللَّهَ لَمْ يَضَعْ دَاءً إِلَّا وَضَعَ لَهُ شِفَاءً غَيْرَ دَاءٍ وَاحِدٍ الْهَرم» . رَوَاهُ أَحْمد وَالتِّرْمِذِيّ وَأَبُو دَاوُد

Usama b. Sharik told that when God’s messenger was asked whether they should make use of medical treatment he replied, “Yes servants of God, make use of medical treatment, for God has not made a disease without appointing a remedy for it, with the exception of one disease; viz., old age.” Ahmad, Tirmidhi and Abu Dawud transmitted it.