I think it takes 8–10 years to make a successful career in the field of medicine. To become a doctor, a student must first complete high school, then go on to college. Although a potential doctor can have an undergraduate degree in any field. Most medical colleges offer four and five years of medical programs. You can select according to your choice and requirements. In this many colleges offer clinical clerkship and some do not offer this opportunity to medical students. So, this depends upon medical students which degree they select for starting his/her career.