Oral inflammatory diseases are frequently encountered in both dogs and cats, often presenting unique challenges for veterinarians due to their complex nature and, at times, poorly understood underlying causes. These conditions can be frustrating to manage in practice, particularly as new insights and treatment approaches continue to emerge in this rapidly evolving field. This lecture aims to provide a comprehensive overview of the latest research and advancements in the study of oral inflammatory diseases in companion animals. It will cover the most commonly encountered conditions, including their aetiology, clinical presentation, diagnostic techniques, and evidence-based treatment and management strategies. Particular emphasis will be placed on a practical, hands-on approach to diagnosing and managing prevalent conditions such as Periodontitis, Feline Chronic Gingivostomatitis, Feline Eosinophilic Granuloma, and Canine Chronic Ulcerative Stomatitis which are collectively known to affect over 90% of dogs and cats within their lifetime