My friend's little brother in California was working as a bartender (while taking some pre-req courses at a J.C.) before he was admitted to Chiropractic school.
MD's and perhaps DO's take the Hippocratic Oath.
Hippocratic Oath -- Classical Version,,,,,exert:
I will neither give a deadly drug to anybody who asked for it, nor will I make a suggestion to this effect. Similarly I will not give to a woman an abortive remedy.
Hippocratic Oath -- Modern Version (Post 1964),,,,exert:
Above all, I must not play at God.