what course should i take before proceeding to a medical school?

In the US, you need to have a bachelor's degree before med school. You can major in anything you want, but you need to have taken all the required courses for whatever schools you want to apply to. In general, the courses are biology (some also want genetics), 1 yr of physics, gen chem, organic chem, biochem, calculus, english, and any corresponding labs. Some schools want additional classes-you will have to look at individual schools you want to apply to for that. If you talk to the premed adviser or adviser in college (or still in high school), they should be able to get you started on the medical track. The other big thing (not a course) is medical experience. It can be paid or volunteer, but you need something because they have to reject so many people every year that they want to make sure medicine is really something you want to do. An additional course that a lot do, but definitely isn't required is a Kaplan course to help prepare for the MCAT. This depends on your comfort level with the material and how well you think you can study on your own as opposed to them giving tips and practice tests.

I'm not sure where abouts you are, but I am in Australia. I am doing dentistry at the moment and when I finish plan to get into medicine. Here, you need to complete one uni degree before they let you in. With something like dentistry, I enjoy it and if for some reason medicine does not work out (like the don't accept me), at least I have something to fall back on.

So, I guess do something you enjoy, that you will be happy with just in case medicine doesn't work out for you

You need a bachelors degree in any subject and the premed classes to apply to med school.