Tannerella forsythia is an anaerobic, gram negative species of bacteria of the Cytophaga-Bacteroidetes family implicated in periodontal diseases. 
T. forsythia, sometimes referred to by previous names (including Bacteroides forsythus and Tannerella forsythensis), is a member of the red complex of periodontal pathogens.
- ^ 'Tannerella forsythensis ATCC 43037'
- ^ Cionca, N, et al. "Microbiologic testing and outcomes of full-mouth scaling and root planing with or without amoxicillin/metronidazole in chronic periodontitis." J Perio 2010;81:15-23.