Specificity vs. Synergy Between Single-Strain and Multi-Strain Probiotics for Ulcerative Colitis Treatment: A Review of the Literature

Ulcerative colitis (UC) is a chronic disease marked by mucosal inflammation of the colon, and its prevalence has progressively increased worldwide. Gut dysbiosis is recognized as a key contributor to its pathogenesis. Although conventional treatments are effective in managing symptoms, they often fail to address the underlying gut microbial imbalance, prompting growing interest in microbiota-based therapies. Probiotic supplementation has demonstrated potential to modulate the disease. However, its clinical application is limited by variability in formulations and strain composition. Debate persists regarding the relative benefits of single-strain probiotics (SSPs), which depend on strain specificity, versus multi-strain probiotics (MSPs), which may provide synergistic effects. The literature remains inconclusive, with some studies indicating that MSPs outperform SSPs, while others emphasize the importance of strain specificity. This review describes the mechanistic basis of both approaches and descriptively synthesizes their clinical efficacy in UC management based on the clinical studies published between 2018 and 2025. Several studies report that both SSPs and MSPs are associated with clinical improvements, including reduced disease activity, symptom alleviation, and enhanced endoscopic outcomes. Given the methodological heterogeneity across included studies, comparative findings should be interpreted with appropriate caution. A direct head-to-head trial could provide a better understanding to determine the optimal approach. Advancing toward personalized probiotic therapy may further enhance the clinical application of probiotics for disease management.