Imaam Ibn Qayyim stated:
I have tested it myself; that is, using Faatihah as a medication for others
and myself and saw many wonderful things especially during my stay in Makkah. I
used to feel serious pains such that it almost prevented me from moving during
circumambulation and other periods, so I quickly recited Faatihah and
wiped it on the spot of the pain and it was just as if a stone just fell off. I
tried that several times and used to take a vessel of Zamzam water and
recite Faatihah in it many times and drink it, which gives me strength
and benefit which I have never witnessed in any other therapy. In fact, the
issue is even greater than that. However, it is in accordance with the strength
of faith and soundness of conviction. Allah is the One whose help is sought.
Source: Madaarij
as-Saalikeen bayna Manaazil (Iyyaaka Na‘bud wa Iyyaaka Nasta‘een)