Gastrointestinal symptoms are common in SLE patients, and more than half of them are caused by adverse reactions to medications and viral or bacterial infections. Patients and methods: 40 SLE patients were subjected to full clinical history and examination, kidney function, lipid profile, C 3, C4, ESR, CRP, urine analysis, 24 h urinary protein, stool analysis and culture, mesenteric , celiac , and carotid arteries doppler. In certain patients, when indicated, they underwent CT abdomen, upper and lower GIT endoscopies. 30 healthy controls were subjected to full clinical history and examination, mesenteric, celiac, carotid arteries doppler, stool analysis, ANA. Results; EDV of the mesenteric duplex is significant lower in SLE patients as compared to controls, prevalence of giardiasis in SLE patients was 30%. Biopsies of the bowel revealed 100% lymphocytic infiltration. Conclusion; increased vascular stiffness of mesenteric duplex, increased prevalence of giardiasis in SLE patients as compared to controls, all bowel biopsies revealed chronic lymphocytic infiltration.