It is narrated from Sayyidah Asma' bint Umays (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) looked at her sons, the sons of Ja'far, and said: "Why are their bodies so thin?" She said: The evil eye quickly afflicts them; may I perform ruqyah for them? He (peace and blessings be upon him) said: "With what?" So she presented to him (peace and blessings be upon him) words in which there was nothing objectionable, and he (peace and blessings be upon him) said: "Perform ruqyah for them."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20747