The purpose of this study is to determine if Rifaximin decreases serum and urine levels of bacterial byproducts and inflammatory markers in patients with chronic kidney disease and to evaluate changes in the bacterial content of the stool from these individuals.

Inclusion Criteria:

• Chronic kidney disease with eGFR ≤ 39 ml/min/1.73m2

Exclusion Criteria:

• Patients with normal renal function or those with less advanced kidney disease
• Inability or unwillingness to provide consent
• Patients undergoing hemodialysis or peritoneal dialysis therapy or those who have undergone organ transplant
• Patients who may be pregnant
• Hemodynamically unstable patients
• Patients with liver failure, pancreatic insufficiency, or inflammatory bowel disease
• Patients with ongoing or recent infection and those with history of C-diff infection
• Patients with abnormal bowel structure secondary to surgical or anatomic variations
• Patients on certain medications including immunosuppressants, antidiarrheal agents, bile acid sequestrants and current or recent (within the last 3 months) use of antibiotics

11 days