The history of studying inflammatory bowel diseases (IBD) spans more than a century. One of the earliest documented descriptions of inflammatory bowel disease dates back to 1859. Since then, these conditions have undergone significant pathomorphosis. This review analyzes current data on the causative factors contributing to the development of IBD, as well as the pathogenetic mechanisms underlying inflammatory bowel diseases and the evolution of their clinical presentation. Particular attention is given to therapeutic strategies and the effectiveness of anti-inflammatory treatment, taking into account the patient’s age and disease severity. Special focus is placed on inflammatory bowel disease unclassified (IBDU), which occurs in pediatric practice nearly twice as often as in the adult population. IBDU may represent either a transitional stage toward ulcerative colitis or Crohn’s disease, or a distinct stable phenotype. The etiology and pathogenesis of the disease are considered to result from a complex interaction between genetic factors, intestinal dysbiosis, and environmental influences. The clinical characteristics of IBDU in children demonstrate a more favorable long-term prognosis, with a lower need for surgical intervention and biological therapy compared to classical forms of IBD. Materials and Methods: To address these objectives, a search of randomized controlled trials and meta-analyses published in contemporary domestic and international literature over the past five years was conducted using specialized electronic databases (PubMed). Conclusion: According to current literature, the incidence of IBD is steadily increasing in both adults and children, with a notable trend toward younger age at onset. Priority therapeutic approaches in pediatric IBD include systemic and topical anti-inflammatory therapy with glucocorticosteroids, immunosuppressive therapy with thiopurines, and targeted biological therapy.