Objective: The main purpose of this review is to systematize the data on the effectiveness of Bifidobacterium longum 35624 in the treatment of patients with irritable bowel syndrome (IBS).

Materials and Methods: Studies were searched in the electronic databases MEDLINE/PubMed, EMBASE, Cochrane, and the Russian Science Citation Index (RSCI) based on the Scientific Electronic Library. The analysis included papers published between January 2000 and November 2023 (inclusive).

Results: The final analysis included 5 studies in 796 patients with IBS carried out in France (n = 2), Ireland (n = 1), Great Britain (n = 1) and Russia (n = 1). Two studies used the Rome II Diagnostic Criteria for IBS, and three studies used the Rome IV. The conducted studies, the findings of which were summarized in this systematic review, have convincingly shown that the use of Bifidobacterium longum 35624 in patients with IBS contributes to the regression of disease symptoms and an improvement in the quality of life. Recent observational studies with different follow-up periods have shown that an extended course of Bifidobacterium longum 35624 results in a more pronounced clinical response compared to the standard duration of the probiotic course (30 days).

Conclusions: This systematic review has demonstrated that the use of Bifidobacterium longum 35624 in patients with IBS, particularly an extended course of up to 3 months, contributes to the regression of disease symptoms and improvement in the quality of life.