Probiotic (VSL #3) for Gulf War Illness

Inclusion Criteria: 1. First GW veterans, Men and women age 35-75 years, 2. Rome III criteria for IBS and two or more of the non-intestinal symptoms (chronic-once a week or more often-fatigue, joint pains, insomnia, general stiffness, and headache) 3. Symptoms of \> 6 months duration, 4. No significant findings on physical examination, Complete Blood Count (CBC) and clinical chemistry panel. 5. Normal gross appearance of the colonic mucosa other than erythema and polyps 6. Negative Tissue transglutaminase (TTG) for celiac disease, 7. Normal thyroid function. 8. Veterans with psychological disorders will not be excluded but will be identified for sub-group analysis. 9. Stable medication regimen for more than a month Exclusion Criteria: 1. Current evidence of any lower gastrointestinal disorder such as celiac disease or inflammatory bowel disease 2. History of/or presence of systemic malignancy (patients with skin and other cancers in remission for more than 5 years are allowed in the study 3. Clinically significant chronic disease: HIV, cardiac, pulmonary, hepatic or renal dysfunction. 4. Presence of Giardia antigen, and Clostridium difficile toxin in stool, 5. Abnormal blood test for thyroid stimulating hormone, tissue transglutaminase antibody 6. Current effects of drug or alcohol abuse 7. Investigator perception of patient's inability to comply with study protocol 8. Recent change in gastrointestinal medications 9. Use of any antibiotic in the last 1 months 10. Positive pregnancy test 11. Subject is currently participating in another research protocol that could interfere or influence the outcome measures of the present study.