The Church was the incubator of the scientific process, and its universities were the seed from which has grown Western scientific thought. Furthermore, western medicine and science have grown within a fundamentally Catholic understanding of reality. That reality is that God made the created world, along with the Laws of Nature by which it is governed. God, of course, is the infinite omnipresent power in the universe. He also made angels, man, and the lower animals.
Demons are fallen angels.
All His creation must obey His Laws of Nature, which are described and codified by scientific inquiry, as well as the Natural Law, which is written on our souls, summed up in the Ten commandments and the Great commendment of Jesus Christ, and codified within the sciences of philosophy and theology. Of course, we were created perfect, but disease and death entered the system with the Original Sin of Adam and Eve. That is a simplistic summary of the reality of our existence, properly understood by science and philosophy and theology. We are created physical bodies, imbued by God with an eternal soul, living a finite Earthly life. We are forced to live according to the Laws of Nature and the Natural Law, and we cope daily with disease and death, the price of sin.