At the minimum, algebra and statistics, gleaming for what was useful for my limited experience in med school so far. You don't need math for orgo lecture (unless your school does?) though you'll use dimentional analysis and conversions in lab.
If you really want to understand physics and chem, calculus will serve you well. But to do well in calc it's important to have good algebra skills as well as knowledge of trig (trig is also important for physics, for the record).