Signs of disease originating in the oral cavity are a common cause for presentation in general practice. The initial reason for presentation is often vague, such as a smelly or painful mouth or difficulty with eating. There is often a simple explanation for what the owner has identified as a problem; however, it pays to keep an open mind and to have a thorough approach to dealing with these cases, as there can sometimes be a more serious or sinister cause. This chapter considers trauma, initial approach to the non-emergency presentation, common problems and changes in oral mucous membranes. Quick Reference Guides: Examining the mouth in a conscious dog; Scaling and polishing teeth; Tooth extraction.