Currently, the problem of diarrheal syndrome against the background of therapy with non-antimicrobial drugs, with a frequency of occurrence of up to 24%, has become particularly relevant. This is due to an increase in the number of people taking drug therapy for a long time, an increase in the population of older people, an increase in comorbidity, polypragmasia and hypersensitivity of this group of patients to medications. The mechanism of drug-induced diarrhea is complex and insufficiently studied. Many drugs are able to affect various pathogenetic links, causing disorders of the intestinal microbiome, motor evacuation dysfunction, layering on existing intestinal diseases with the development of functional disorders, catarrhal and erosive ulcerative lesions, which makes it difficult to diagnose and choose an adequate therapeutic tactic. The situation is often complicated by the impossibility of canceling the therapy of the underlying disease or changing the treatment regimen, which can lead to serious consequences for a patient with diarrhea syndrome. Thus, the issues of early diagnosis, differential diagnosis and approaches to the treatment of drug-induced diarrhea are becoming increasingly important in clinical practice.