No, it doesn't matter, you just have to ensure that you get good grades and find the room for prerequisite courses in there. I also think it's best to get a "practical" major - one where you could get a reasonably interesting and adequately paid position in case med admissions doesn't pan out on the first try (or second...). It's nice to be able to have smth to fall back on. Some majors will give you better employment prospects than others (think business, economics), but there is also the option of doing an MA/MS in your field after you graduate if you don't get into med right away.