Background: Growing body of evidence suggests a functional interplay between gut microbiome, intestinal barrier and immune system. That so-called „gut-skin axis” has been considered as a key factor in the etiology of psoriasis. The aim of this study was to compare psoriasis severity, intensity of self-reported gastrointestinal symptoms and concentration of gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) between psoriatic patients with and without altered intestinal barrier. Type of Study: Cross sectional study. Methods: One hundred consecutive patients with chronic plaque psoriasis (57 men, 43 women), with a mean age of 43.6 years, were enrolled. Gastrointestinal symptoms were evaluated with a validated questionnaire – Gastrointestinal Symptom Rating Scale (GSRS). To examine gut barrier integrity we investigated serum concentrations of claudin-3, a modulator of intestinal tight junctions and intestinal fatty acid-binding protein I-FABP, a marker of enterocyte damage. TMAO concentration was measured through high performance liquid chromatography. Results: Patients with altered gut barrier showed significantly higher score in GSRS (p<0.05), especially in “indigestion” section. Moreover, patients with psoriasis and disrupted intestinal barrier demonstrated higher disease activity (PASI: 18.9±1.9 vs 10.1±2.5, p<0.05). The inflammatory parameters and markers of bacterial translocation (TMAO) were significantly higher in a subgroup of patients with damaged gut integrity (p<0.05). Presence of metabolic syndrome and its components did not differ significantly among the groups. Conclusion: Our results support the hypothesis that alterations of the intestinal barrier may play an essential role in the pathogenesis of psoriasis. Further study should focus on developing therapies that enhance intestinal barrier function.