Inflammatory bowel disease in humans and animals is a chronic condition of unknown origin that is becoming increasingly common. In humans, it is known as Crohn’s disease and ulcerative colitis, which primarily differ in the part of the digestive system affected by inflammation. In dogs and cats, inflammatory bowel diseases are named based on the inflammatory infiltrate found in the intestinal mucosa. Inflammatory bowel diseases in humas and animals exhibit certain similarities differences, with the main connection being that the pathogenesis, as well as the cause of the disease, is not fully understood. Among the most important issues, dysbiosis, gene mutations in Toll-like and NOD2 receptors, defects in antigen-presenting cells, depending on the type and prevailing disease, Th1 or Th2 cell populations, and the production of pro-inflammatory mediators, are highlighted. All of these irregularities contribute to the onset and continuous reactivation of inflammation. Some external factors, more extensively studied in humas, have been identified as risk factors for the disease. Due to the increasing number of patients with inflammatory bowel disease, there is a need for research and clarification of the unknowns of this disease in veterinary medicine. Inflammatory bowel disease manifests as chronic gastrointestinal symptoms with episodes of exacerbation and remission with possible extraintestinal complications in humas. Diagnosis of the disease is problematic and there is no standardized method. Depending on the severity of the disease in humans, medications such as corticosteroids, immunomodulators, TNF inhibitors and integrin receptor antagonists are used. Dogs and cats mostly respond well to corticosteroids, immunomodulators, antibiotics and proper nutrition.