RASULULLAH (sallallahu alayhi wasallam) said: “Jibraeel taught me a medicine which obviates the need for any other medicine or for a physician.”
Hadhrat Abu Bakr, Hadhrat Umar, Hadhrat Uthmaan and Hadhrat Ali (radhiyallahu anhum) eagerly asked: “And, what is that medicine? We are in need of it.” Rasulullah (sallallahu alayhi wasallam) said:
“Take some rainwater and recite on it Surah Faatihah, Surah Ikhlaas, Surah Falaq, Surah Naas and Aayatul Kursi.
Each one seventy times (and blow on the water). Then drink of this water morning and evening for seven days.
I take oath by That Being Who has sent me as the Nabi with the Haqq! Jibraeel said to me: ‘Verily, whoever drinks from this water Allah will eliminate from his body every disease and protect him against all sicknesses and pains. Who-ever gives it to his wife to drink, then sleeps with her, she will become pregnant by the permission of Allah. It cures the eyes, eliminates sihr (magic), cures chest pains, toothache and urine stoppage, etc., etc…………” (End of Hadith)

There can be absolutely no doubt in the efficacy of this wonderful remedy prescribed by Jibraeel (alayhis salaam) by the Command of Allah Azza Wa Jal. It has been handed to the Ummah by As-Sadiq (The T r u t h f u l ) , Muhammad Rasulullah (sallallahu alayhi wasallam).
Its efficacy is dependent on two conditions just as the efficacy of all kinds of remedies is reliant on certain conditions, e.g. diet, dosage, etc. The two essential conditions for its efficacy is:

(1) Taa-at (Obedience). Abstention from sin – fisq and fujoor, and cleansing the heart from malice, etc.
(2) Yaqeen – firm faith.
The ultimate result is the decree of Allah Ta’ala with which every Mu’min has to incumbently be pleased. Allah does as He wills.