What is the most common word for medicine? (the physical substances, not the field of study) seems to be the field of medicine might be another word for the field of medicine? is the word I found listed most often. However, I also saw and but don't know what the differences between these words are.

No comparison; Go with {} or as a patient or someone on the patient's side. It is hard to beat kun-yomi words in intuitiveness.

and are too technical/academic for everyday conversations unless you are a medical professional.

and do not even mean in the first place. Those words refer to the study/field of Medicine.