The author gives an account of the history of the dental foci from the ancient times up to the present day, together with the change of the concept of dental foci and their modern interpretation. The article points out the shift in the assessment of the importance of focal infection. It gives a detailed account of the focal infection of dental origin, as well as the consequence of such inflammation. Mentions the phenomenon of tropism and its role in the development of secondary diseases. The article is based upon an excessive literature.