Question: What is the ruling on studying medicine and engineering? Will they be rewarded [for studying it] and will they have reward like the students of Legislated knowledge?
Answer: “Yes, studying the knowledge of medicine, engineering, pharmacy has good in it. If the intention is good, he will be rewarded. He will be rewarded for this if he has the intention to benefit Islam and the Muslims. In this is good. However, it is not like the Legislated knowledge, the knowledge of the Quran and Sunnah. The virtue is only for the Legislated knowledge. This one [who studies engineering and medicine] will be rewarded in accordance to his intention. He will have good and reward in accordance to his intention. Him working and having a profession to earn for himself, his wife, his children, to benefit the Muslims and make them sufficient from the enemies of Islam, then this has good in it according to the intention. In it is also reward. However, the texts and rewards have been reported about Legislated knowledge. Verily knowledge is only the three categories which you have heard. Yes”.
[Taken from: https://goo.gl/p1n5tN]
Shaikh Bin Baz rahimahullah said:
“…As for what is connected to the sciences of medicine, engineering, invention, geology, and other than it. Then these are sciences which have its people and according to their purposes, they will have their ruling. So whoever studies engineering or medicine to benefit the Muslims and suffices them from their enemies, then this one is rewarded according to his intention….”
[Noor ‘ala Darb (1/557)]
Faisal Ibn Abdul Qaadir Ibn Hassan