Is streptococcus viridans found in throat harmful or beneficial?

Let me explain: The organisms are most abundant in the mouth, and one member of the group, s. Mutans, is the etiologic agent of dental caries in most cases and populations. Others may be involved in other mouth or gingival infections. If they are introduced into the bloodstream, they have the potential of causing endocarditis, particularly in individuals with damaged heart valves.