Here the investigators propose to preliminarily investigate the safety and effects of probiotics in infants in Bangladesh through a pilot randomized clinical trial. The investigators hypothesize that two probiotics are safe for infants in Bangladesh and may have an effect on biomarkers of gut health and immunity. The specific aims of this pilot are: i) to confirm the safety of administering probiotic strains to infants in low-income countries, ii) to determine the effects of dosing frequency on colonization and persistence of probiotics in the GI tract, iii) to measure markers of intestinal and immune function and microbiota structure.

Inclusion Criteria:

• Healthy infants.
• Infants 1 -3 months of age at the beginning of the study.
• Parents/guardians of each subject are able to understand study procedures and agree to participate in the study by giving consent.
• Parents and child are planning to remain in Dhaka for the next four months.

Exclusion Criteria:

• Infants with known birth defects.
• Infants who have been hospitalized.
• Infants who have an acute infection or illness at the time of enrolment.
• Infants who are currently taking antibiotics
• Infants <1 month of age or >3 months of age.
• Infants three standard deviations below mean on anthropometric measures (will be referred for medical care).
• Infants who are already receiving a probiotic product or treatment.
• A diagnosis or suspicion of immunodeficiency disorder.
• A diagnosis or suspicion of bleeding disorder that would contraindicate venipuncture.
• Family residence outside of Dhaka or families expecting to move outside of Dhaka in the next 4 months.