"... fully functional?" FULLY FUNCTIONAL!

This may be the most messed-up scene in Star Trek canon. In the whole hospital, he is there mortified at "the dark ages!" and implies his peers here are SO ignorant and incompetent at practicing medicine. Over and over. Dude, when did you become a cranky entitled old man complaining about everyone else? Because you're from another time, you have to hate on these doctors?

He's not her doctor, and knows nothing but that she claims she's on dialysis. Still he gives her a life-altering medication. Which should help, sure, but damn, you don't know anything about her case. There's no informed consent.

He keeps these miracle pills right in his pocket to heal people like Jesus. Does this regenerate other things? Does he always bring them along? I assume he didn't pack this morning and say "better bring this one, in case someone has kidney failure on the mission"

McCoy is kind of a dick here. The ends doesn't justify the means. New kidney aside, that was a dick move.