The thesis studies the different bacterial infections affecting childhood. How important is the early diagnosis, what are the causes of these diseases and their symptoms, with emphasis on the orofacial manifestation.It tries to help whoever reads the thesis, to understand better the subject, and help in the differential diagnosis between one another, because even now days it is sometimes still hard to diagnose correctly the diseases. Children affected with these diseases usually require a more complex treatment and of course special precautions are needed when treating them.