This study will evaluate the safety and tolerability of the probiotic Lactobacillus reuteri (LR) in healthy adult patients. Patients will be randomized to receive either LR or placebo orally each day for a total of 60 doses. The effects on fecal bacteria, circulating white blood cell receptors and inflammatory cytokine profiles will be measured.

Lactobacillus reuteri oil drops are a natural product containing Lactobacillus reuteri (LR), which has traditionally been used for the establishment and maintenance of a well-functioning gastro-intestinal (GI) tract micro flora and prevention and treatment of mild diarrhea associated with GI-tract infections. The oil drops contain a dietary supplement of Lactobacillus reuteri DSM 17938. The patients will receive 5 drops (10^8 live organisms) by mouth daily for 60 days. Daily administration will include 5 drops (5x10^8) of L. reuteri or placebo daily for two months. During this time,circulating peripheral blood mononuclear cell (PBMC) toll-like receptor-2 and -4 levels will be measured, along with PBMC cytokine production levels in vitro. Fecal DGGE analysis(with sequencing of bacterial rDNA) will be completed identifying changes in fecal microbiota. Inflammation in the gut will also be assessed by fecal calprotectin assay (ELISA). The time on study treatment is 2 months, with 4 months observation, for a total of 6 months. There will be 7 required visits, during which, we will assess safety and immune system effects.

Inclusion Criteria:

• Healthy Adults (18 - 60 years old)
• No other recognized illness

Exclusion Criteria:

• Pregnancy or breastfeeding
• Patient taking immunosuppressive medications, including oral corticosteroids
• Positive result of HIV, Hepatitis B, and/or Hepatitis C test
• Abnormal lab test results
• Gastrointestinal related diseases and surgeries
• Patients with an allergy to antibiotics
• Presence of fever or a pre-existing adverse event monitored in the study
• No more than two study participants in one household
• Use of probiotics in the last 90 days
• Diarrheal illness within the past 30 days
• Recent or current use of oral antibiotics /anti-fungals(in the past 2 weeks)
• Current use of oral laxatives
• Chronic alcohol use or more than 1 drink per day
• Subjects with implanted prosthetic devices including prosthetic heart valves
• Known sensitivity to sunflower oil or products containing linolenic/oleic acids
• Will require that subject not take any other probiotic-containing products, including yogurt supplemented with probiotics during the 6-month period