Peter Pormann and Emilie Savage-Smith write about the healing power of al-Fatiha in their book "Medieval Islamic Medicine:"
"Treatises on Prophetic Medicine also advocated in varying degrees folkloric and magical remedies in addition to numerous invocations for warding off afflictions and protecting from jinn and the Evil Eye. The early tract based on Shi'ie imams had, for example, the following prescriptions:
He (the Prophet) said: 'Keep many domestic animals (dawajin) in your houses so that the demons are occupied with them instead of your children.'
(The imam Ja'far ibn Muhammad) al-Sadiq said to him (one of his clients whose fever would not subside): 'Undo the buttons of your shirt and put your head in it. Recite the call to prayer (adhan) and the introduction to prayer (iqamah), and recite seven times the 'surah of praise' (Al-Hamd, that is, the 'Opening', al-Fatihah, no.1).' The man said: 'I did that and recovered as quickly as a camel loosened from its cord.'
He (al-Sadiq) said to him (someone suffering from colic (or intestinal obstructon, qawlanj): 'Write for him the opening (surah) of the Qur'an (al-Fatihah, no.1), the surah 'Purity' (al-Iklhas, no. 112), and two surahs for seeking protection (al-ma'udhatan, the last two surahs of the Qur'an, 'Dawn', al-Falaq, and 'People', al-Nas, nos. 113 and 114). Then write underneath: "I take refuge in the presence of God, the Great, and in His might, which is unceasing, and in His power, which nothing can resist, from th evil of this pain, and the evil within it." Then swallow it with rainwater on an empty stomach. You will be cured of it, God the Exalted permitting.' " (2007, p. 150).
~Excerpted from "Medieval Islamic Medicine" by Peter E. Porman and Emilie Savage-Smith.