The review presented here covers metastatic local and systemic disease secondary to the accumulation of plaque or the formation of other pathogenic microbial depots in the mouth. At least 3 pathways may link oral infection to secondary disease, to wit metastatic infection due to transient bacteremia, metastatic immunological injury, and metastatic toxic injury. The available evidence is presented and examples are provided. They concern among others such divergent diseases as acute bacterial myocarditis, infective endocarditis, brain abscess, uveitis and iridocyclitis, trigeminal and atypical facial neuralgia, unilateral facial paralysis, fever of "unknown' origin, and neutrophil dysfunction.