In medicine, a doctor (or “physician”, “practitioner”, “doctor of medicine”) is a health-care professional in charge of healing or preserving the human health. A doctor is someone who earned a doctoral degree, a PHD, through a successful completion of coursework, or through an assessment of his high level of competence in research. A doctor in medicine is someone who holds the degrees of Doctor of Medicine.

The journey to become a medical practitioners is a very long one. In the so-called “developed countries” it takes more than 6 years to complete a doctoral degree. Courses are based on fundamental sciences: anatomy, physiology, biochemistry...In many countries, most students fail to complete successfully their very first year in medicine. As they get ahead in their study, they may specialize in a particular medical field. Anyway, after they graduate, they don't hold a full license to practice medicine without supervision, so they must complete a 1 or 2 years internship in a hospital.

Medical practitioners (doctors) make use of their knowledge to give diagnosis and treatment of disease. There are several ways to practice medicine. Either you become a general practitioner or a specialist or a surgeon. General practitioners provide "basic" cares. They may cure chronic disease and play a very important social role (for they provide health prevention). Also, when a GP detect some kind of medical problem on a patient, he/she is capable of commending his/her patient to a specialized colleague who will best able to find and cure a specific disease.