It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "O people, seek treatment, for Allah, the Mighty and Majestic, has not created any illness without creating a cure for it, except death." (Al-sam means death.)
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11289