It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) went to visit a sick person and said: "Why do you not call a doctor for him?" They said: O Messenger of Allah! Are you also commanding us to do this? The Prophet (peace and blessings of Allah be upon him) said: "Allah the Exalted has not sent down any disease except that He has also sent down its cure."
Hadith Referenceسلسله احاديث صحيحه / الطب والعيادة / 1615