Actually, the above post is only partly correct.
English and History majors have some of the highest acceptance *percentages*, not raw numbers. The reason for this is obvious--only the English majors who are stellar applicants actually apply to med school, whereas dang near every bio major applies.
Most med school freshman, you will find, actually majored in a science, usually biology or a related discipline.
With that said, it does not matter all that much what you major in, as long as you complete the necessary pre-med classes (biology, chemistry, physics, org. chem). It can matter what school you go to, though.
The more well-known your school, the better your chances are. I have been told that, more important than this, is that you try to attend an undergrad school that actually *has* a medical school as well, probably the one you want to attend. The school has to believe in their own product (you), so they always show some preference to their own grads when selecting from applicants.