For a long time, it has been the speculation that teeth might be the underlying cause of various distant systemic diseases. A dental focus is traditionally defined as localized chronic infection that under certain circumstances may result in local or systemic disease. The most frequently reported dental foci are periodontitis, periapical lesions, teeth with non-vital pulp, root tips and partially impacted molars. The proposed mechanism of action of by dental foci is based on the hematologic spread of bacteria and/or their toxins into the body. Foci of infection have historically been postulated to arise from the tonsils, adenoids, sinuses and oral cavity with less common foci from the prostate, appendix, gall bladder and kidney. Focal infections attributed to foci of infection have included arthritis, neuritis, myalgias, nephritis, osteomyelitis, endocarditis, brain abscesses, prosthetic joint infections, skin abscesses, pneumonia, asthma, anemia, indigestion, gastritis, pancreatitis, colitis, diabetes, and so on. The three most documented, publicized and litigated examples of focal infection are bacterial endocarditis, brain abscess and orthopedic prosthetic joint infections. Opinions abound on many aspects of these infections, but little attention has been paid to the absolute risk to the patient that these infections pose from dental-treatment-induced bacteremias.