This chapter focuses on the aetiology (impaired self‐cleaning of the dentition due to primary malocclusion, high‐carb food, plaque formation, malpositioned teeth) and pathogenesis of periodontopathies (local gingivitis, periodontitis, apical abscessation and loosening of teeth) and caries lesions in herbivorous rodents and omnivorous rodents. Diagnosis and treatment of species‐specific findings in guinea pigs and chinchillas are presented as well as specific pathological changes in omnivorous rodents that are mostly missed in praxi. A consequent prophylaxis of these changes is recommended at the end of the chapter.