Ca-Mg Butyrate in GWI

Inclusion Criteria: * Gulf war era veteran deployed 40 and 70 years old, in good health by medical history prior to 1990 meeting GWI case definition of CDC and Kansas criteria and * currently have no exclusionary diagnoses (self- reported) that could reasonably explain the symptoms of their fatiguing illness. The severity of illness is moderate to severe, scoring less than 30 of 100 on the physical domain of VSF36 . Exclusion Criteria: * Untreated schizophrenia, * Untreated bipolar disorder, * Untreated delusional disorders, * Untreated dementias of any type and * active alcoholism or drug abuse. * Medical conditions excluded include (i) organ failure, (ii) defined rheumatologic inflammatory disorders, and (iii) transplant. * Use of Butyrate in any form in the 3 months prior to study drug, medications that would impact gut motility, diarrhea, chronic pain, and immune function e.g., steroids, (Last 3 months) * immunosuppressive drugs or biologic response modifiers within 3 months of study entry will be used as exclusion criteria. * Pregnancy, or planned pregnancy in the next 6 months, * Body mass index more than 35 * Specific diets that may have enhanced or enriched fiber or butyrogenic formulations (FODMAP) * Medications that could potentially impact immune function in the past one month will be excluded (e.g., steroids, antibiotics, immunosuppressives; * Medications containing supplement calcium or magnesium butyrate should not be taken for at least 3 months before study entry. * Nutraceuticals that are formulated to impact gut microbiome or immune health) and use of drugs that affect GI motility and use of any antibiotic in the last 2 months. * Known allergy to butyrate supplements or their derivatives such as sodium salts or hydroxy derivatives of butyrate and/or inactive ingredients of active and placebo soft gelatin will also be excluded. * Current evidence of celiac disease or late-stage cirrhosis of the liver, Giardia antigen presence, Clostridium difficile toxin in stool, tissue transglutaminase antibody, recent change in gastrointestinal medications, use of drugs that affects gastrointestinal motility, and use of any antibiotic in the last two months also will be excluded.