Answered by Mufti Mohammed Tosir Miah
Question:
Virtues of Surah Fatihaa
Answer:
There are many virtues and blessings of Surah Fatiha. It is narrated by Saaiduna Abu Saeed Ar Rafi bin Al- Mu’alla 
that the Prophet of Allah 
said; “Shall I teach you the greatest Surah in the Qur’an before you leave the mosque?” Then He took me by the hand, and when we were about to step out, I reminded him of his promise to teach me the greatest Surah in the Qur’an. He said; “It is Alhamdulilahi Rabbil Alamin (Surah Fatiha) which is ‘As-Sab al Mathaani’ (i.e. the seven oft repeated verses) and the great Qur’an which is given to me.” (Surah Bukhari p.749 v.2)
One of the many benefits, which Surah Fatiha can be used for, is to cure people who might be inflicted in different types of diseases.
Saaiduna Saeed al- Khudri narrates that while on a journey we halted at a place. A girl came to us ad said; “the cheif of this tribe has been strung by a scorpion and our men are not present, is there any body amongst you who can recite something upon him to treat him?” Then, one of our men went along with her although we did not think that he knew any such treatment. However, our friend went to the chief and recited something upon him and the chief was cured. Thereupon, the chief gave him thirty sheep and gave us all milk to drink. When he returned, we asked our friend: “Did you know anything to recite upon him to cure him?” He said; “No, I only recited Umm al Kitab (Surah Fatiha) upon him.” We said do not do anything until we reach Madinah and ask the Prophet regarding the (practice and reward whether the sheep were lawful for us or not). Upon reaching Madinah, we narrated this to the Prophet , whereupon he remarked: “How did he come to know that Al Fatiha can be used as a cure? Distribute amongst yourselves your reward and allot a share for me as well.” (Sahih Bukhari p.749 v.2)
Saaid Bin Yazeed says that the Prophet of Allah recited Surah Fatiha and blew it on me to safeguard me against calamities. The Prophet of Allah recited this Surah and put his blessed saliva in my mouth.” (Tabaraani In Al’Awsat)
The Prophet of Allah said; “In the Fatiha of the Quran, there is a cure for all maladies. (Sunan Darimi)
From the aforementioned ahadiths we can deduce that Surah Fatiha can be recited outside of Salah in particular in those cases where people might be afflicted with illness or calamities.
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham.