Patients suffering from irritable bowel syndrome with prevailing diarrhea associated with obesity were characterized by high levels of C-reactive protein, fibrinogen and average molecules, increased content of pro-inflammatory cytokines (TFNα and TGFβ1) with a decreased content of IL-10, as well as imbalance of the pro-oxidant and anti-oxidant blood systems (increased content of 8-isoprostane and ceruloplasmin). The gene discussed is CRP; the disease is Obesity.