The purpose of this research is to collect data from patients diagnosed with functional dyspepsia who are treated with glutamine and describe safety and treatment results compared to patients taking a placebo. Glutamine, an essential amino acid in humans, is an important energy source for cells lining the gastrointestinal tract and has been shown to play an important role in regulating the strength of the intestinal wall.

Inclusion Criteria:

• Meet Rome IV criteria for functional dyspepsia (https://theromefoundation.org/rome-iv/rome-iv-criteria/)
• Patients will generally be in good health. During initial evaluation, patients' symptoms will be assessed and patients categorized into either the PDS, EPS or mixed subtype of FD.

Exclusion Criteria:

• Significant comorbid illness
• Symptoms are thought to represent an organic disorder (e.g., peptic ulcer disease, hepatitis, pancreatitis, inflammatory bowel disease, type I diabetes, a known malignancy, radiation-induced injury, an active infection, vasculitis, celiac disease), or if the patients have known esophagitis, eosinophilic esophagitis or H. pylori.
• Prior surgery to the esophagus, stomach or duodenum will be excluded, as will those taking proton pump inhibitors (PPIs), opioids, corticosteroids and those taking regular (daily) antihistamines, non-steroidal anti-inflammatory drugs (NSAIDs), or mast-cell stabilizing agents within the prior 2 weeks. Of note, patients taking PPIs will be given the opportunity to discontinue their PPI in favor of famotidine 20 mg daily for 2 weeks before enrollment.
• Known allergies to lactulose: mannitol.
• Active tobacco use and excessive alcohol use (defined as 8 or more drinks per week for women or 15 or more drinks per week for men; http://ww.cdc.gov)
• Co-existing IBS will be allowed to enter the study as long as symptoms are not predominant.
• Hepatic and renal impairment within the past 6 months. Defined as AST/ALT > 2X ULN, Total Bilirubin > 2 X ULN, Estimated Glomerular Filtration Rate (eGFR) of < 60 mL/min/BSA.
• Diagnosed with galactosemia.
• Pregnant or breastfeeding women.
• Patients with documented or reported lactose intolerance.