وَنُنَزِّلُ مِنَ الْقُرْآنِ مَا هُوَ شِفَاءٌ وَرَحْمَةٌ لِلْمُؤْمِنِينَ ۙ وَلَا يَزِيدُ الظَّالِمِينَ إِلَّا خَسَارًا
We send down (stage by stage) in the Qur'an that which is a healing and a mercy to those who believe: to the unjust it causes nothing but loss after loss.
The Hadith states, "Hold on to (the essential use of) the 'black seed', for certainly in it is a cure for every sickness except (the sickness which Allah has decreed for one's) death".
^^^^ If people want to leave the clear path of Qur'aan and Sunnah and go to doctors for bloodtests, urine tests and stool tests that's their prerogative!


