(Sayidah) Aishah narrated that the Prophet ﷺ said, ‘Indeed this black seed is a cure for every illness, except for al-Saam.’ I (Aishah) said, ‘What is al-Saam?’ He ﷺ said, ‘Death.’ (Sahih al-Bukhari, 5687).
The scholars differ over the interpretation of this Hadith. Some have said that it is not to be taken literally, in that it covers all illnesses, rather it is interpreted to mean certain types of illness.
وَاخْتَلَفَ الْعُلَمَاءُ فِي ذَلِكَ فَقَالَ أَكْثَرُهُمْ هَذَا مِنْ الْعَامِّ الْمَخْصُوصِ (طرح التثريب في شرح التقريب)
The scholars have differed regarding it (the Hadith), most of them said it is from the narrations that use general wording but intend something more specific. (Imam al-Iraqi, Tarh al-Tathreeb).
This Hadith uses general wording but intends something more specific. As no plant or tree encompasses all capabilities to combat every feature required in the cure of ailments, due to the difference in their nature. Rather what is intended is a cure from every illness that relates to moisture or mucus. (Imam Abu Sulayman al-Khattabi, A’laam al-Hadeeth).
وَقَالَ الْقَاضِي عِيَاضٌ وَالنَّوَوِيُّ هُوَ مَحْمُولٌ عَلَى الْعِلَلِ الْبَارِدَةِ (طرح التثريب في شرح التقريب)
(Imam) Qadi Iyaad and (Imam) al-Nawawi both said, the Hadith is to be understood to refer to illness that relate to cold. (Imam al-Iraqi, Tarh al-Tathreeb).
So we see above that some of the great Imams in our religious tradition have interpreted the Hadith rather than taking it literally. It is important to know that such a move away from the literal meaning is only permitted when there is evidence to do so. The primary evidence for these scholars is the fact that the Prophet ﷺ instructed people to consume other things for medical difficulties e.g. honey and advised certain practices e.g. cupping.