The minimum is generally one year of gen chem, one year of orgo, one year of biology, one year of physics, all with labs. Some schools make you do biochem, and some make you have a year of english and/or a year of math.
I don't know if it looks bad if you don't take more; they like see more advanced courses, I think ,but if you're a non-science major then I guess they don't expect that as much.