Is the Quran a cure for all diseases?
The Quran introduces itself as a cure: “O mankind, there has to come to you an instruction from your Lord and healing شِفَٓاءٌ for what is in the breasts الصُّدُورِ and guidance and mercy for the believers.” (Yunus [10] 57. Also: Fussillat [41] 44; al-Isra [17] 82).
According to the traditional understanding the Quran should be read for curing all diseases such as heart attack, paralysis, infertility, psychiatric disorder etc. However, the healing in the Quran is related only to belief and moral problems which are in the breasts and hearts.
The Quran tells us what it means about healing in Yunus [10] 57, one of the three Verses: The healing that is in the breast! فِي الصُّدُورِ . Anyway, medical diseases are not only in the breast, they could be in every part of the body.
The word marid مَرَضٌ (disease), which is the opposite of shifa (healing) in the Quran, is used for medical diseases too (al-Baqara [2] 184, 185, 196; al-Fath [48] 17; al-Maida [5] 6; al-Muzzammil [73] 20; an-Nisa [4] 43, 102; an-Nur [24] 61; ash-Shuara [26] 80; at-Tawba [9] 91) . However, the Quran uses the word “diseases in the breast” only for belief and moral problems: Sexual perversion (al-Ahzab [33] 32); slander (al-Ahzab [33] 12; al-Anfal [8] 49); hypocrisy (al-Ahzab [33] 60; Muhammad [47] 20); deny (kufr) (at-Tawba [9] 125); fear (al-Maida [5] 52; Muhammad [47] 20); negative feelings and thoughts (al-Higr [15] 47); doubt (al-Hajj [22] 53; al-Muddathir [74] 31; an-Nur [24] 50); lies (al-Baqara [2] 10).
Therefore, the Quran is a cure and mercy for belief and moral “diseases,” not for medical diseases.