Médecin vs. docteur vs. toubib

The French language uses several words such as 'médecin', 'docteur', and 'toubib' to describe the English term for 'doctor' or 'physician'. Although these words are synonymous, their usage may vary depending on the context, formality, and region.

Médecin

Médecin is a formal term used to refer to a doctor or physician. It is most commonly used across all regions of France and signifies any professional in the medical field with a degree in medicine.
Mon médecin me préoccupe beaucoup.
(My doctor worries me a lot.)
Je dois prendre rendez-vous avec mon médecin.
(I need to make an appointment with my doctor.)

Docteur

'Docteur' is a formal term used to refer to someone who has achieved the highest academic degree in any field, not only medicine. While it's also used to address a physician, it's important to consider its broader meaning.
Docteur Martin est mon nouveau dentiste.
(Doctor Martin is my new dentist.)
Le docteur en philosophie donnera une conférence ce soir.
(The doctor of philosophy will give a lecture tonight.)

Toubib

'Toubib' is an informal, colloquial term for 'doctor' often used in spoken language. Its usage can sometimes signify a close relationship with the doctor or can simply be a lighter, more familiar term for 'médecin' or 'docteur'.
Il est temps d'aller voir le toubib, tu ne te sens pas bien.
(It's time to go see the doc, you are not feeling well.)
Mon toubib m'a dit d'arrêter de courir pour un moment.
(My doc told me to stop running for a while.)

Summary

While 'médecin', 'docteur', and 'toubib' all refer to a doctor or physician in French, 'médecin' is the most common and formal term. 'Docteur' however, does not only refer to medical doctor but also any highest degree holder in any field. 'Toubib', on the other hand, is a casual term used informally in spoken language.