In the United Kingdom and many Commonwealth countries, those training for the medical profession complete either a 5-6 year course or an accelerated 4-year graduate entry course that leads to the degrees of Bachelor of Medicine, Bachelor of Surgery (MBBS, MBChB, or other similar abbreviation); the higher postgraduate degree of Doctor of Medicine (MD) is reserved for those who can prove a particular distinction on the field, usually through a body of published work or the submission of a dissertation.

In the United States and some other countries, the basic medical qualification is the Doctor of Medicine (M.D.), usually completed as an advanced degree following a Bachelor of Science (B.S.) degree. The American MD degree is the equivalent of the British MBBS (etc.) qualification. In other health-related disciplines such as podiatry, dentistry, chiropractic medicine, optometry, and veterinary medicine, where the professional doctorate is the degree which serves as the ‘entry-level’ degree for practitioners, a similar educational framework exists and leads to a doctoral degree. Such professionals typically use the title ‘Dr’ professionally and socially, although a podiatrist would often be referred to as a “podiatric physician/surgeon” and a dentist a “dental surgeon” or “dental or oral physician”. In the United States only, the Doctor of Osteopathic Medicine (D.O.) degree is an equivalent degree to M.D. but with several differences in study and training.

Speaking in the House of Commons of the United Kingdom on January 19, 1996, health minister Gerald Malone noted that the title doctor had never been restricted to either medical practitioners or those with doctoral degrees in the UK, commenting that the word was defined by common usage but that the titles “physician, doctor of medicine, licentiate in medicine and surgery, bachelor of medicine, surgeon, general practitioner and apothecary” did have special protection in law.

For many years the UK’s General Dental Council (GDC) regarded the use of the title doctor by dentists as a disciplinary offence, but on November 14, 1995 the GDC ruled that dentists could use the title doctor thenceforth provided that they did not do so to imply that they held qualifications that they did not possess.

In guidance issued by Who’s Who published by A & C Black, it is noted that in the context of the UK, “not all qualified medical [practitioners] hold the [MD] degree” but that “those … who have not taken [it] are addressed as if they had.” A & C Black also note that British surgeons – a designation reserved for those who have obtained membership of the Royal College of Surgeons – are addressed as Mr, Mrs or Miss rather than Dr. This custom has been commented on in the British Medical Journal and may stem from the historical origins of the profession.

In German language-speaking countries, the word Doktor always refers to a research doctorate awardee, and is distinct from Arzt, a medical practitioner. An Arzt who holds the Dr. med. degree is addressed as Herr Doktor; an Arzt who does not would simply be Herr. This rule has been weakened recently, and people (e.g. in Austria) refer to medical practitioners as Doktor too.