It is narrated from Sayyiduna Ali (may Allah be pleased with him) that when the Prophet (peace and blessings be upon him) would go to visit a sick person, he would make this supplication: "O Lord of the people! Remove this distress and pain, grant him healing, for You are the only Healer. There is no healing except Your healing, a healing that leaves behind no trace of illness."
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 565
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف، لضعف الحارث الأعور