This is a three-arm, double-blind, placebo-controlled study to investigate the safety of Lactobacillus salivarius AP-32 and Bifidobacterium animalis subsp. lactis CP-9 used individually in healthy infants.

Infants will be given the content of one capsule (mixed in infant formula or breast milk) twice daily (morning and evening) for 15 weeks.

This is a three-arm, double-blind, placebo-controlled study to investigate the safety of Lactobacillus salivarius AP-32 and Bifidobacterium animalis subsp. lactis CP-9 used individually in healthy infants.

Infants will be given the content of one capsule (mixed in infant formula or breast milk) twice daily (morning and evening) for 15 weeks. Follow-up visits will take place at study days 14±3, 42±3, 70±4 and 105±4.

Caregivers will keep a diary of the volume of formula intake/minutes of breastfeeding, stool frequency and consistency (hard, formed, soft/paste or loose/watery), symptoms of digestive tolerance (regurgitation and flatulence), sleeping time, crying/fussing time and episodes for 3 days before each visit. At each visit, the research team will review the diary and conduct physical examination, including anthropometric measurements (weight, recumbent length, and head circumference).

Fecal samples will be collected prior to the first administration of the assigned study product and at the end of study for microbiota analysis.

Adverse events (AEs) will be assessed based on inquires to the caregivers. AEs will be classified as related or unrelated based on a relationship to study product intake according to the investigator.

Inclusion Criteria:

• Having informed consent of the parent or legal guardian.
• Healthy male and female infants between 7 days and 2 months (60 ± 2 days) of age at the time of study initiation.
• Full term ( ≧ 36 weeks gestation at birth).
• Birth weight ≧ 2500 g.
• Able and willing to comply with all study requirements.

Exclusion Criteria:

• Failure to thrive (weight gain < 100 grams/week average from birth to the last recorded weight).
• Major acute or chronic illness (e.g. significant cardiac, respiratory, hematological, gastrointestinal or other systemic diseases, major developmental or genetic abnormality).
• Use of substances that alter gut microbiota (antibiotics, prebiotics, probiotics or gastric acid inhibitors) within 2 weeks prior to the study initiation.
• For breastfed infants, use of antibiotics, prebiotics and probiotics by the mothers.
• Cow's milk protein allergy.
• Feeding difficulties.
• History of any allergies to maltodextrin.
• Participation in another clinical trial.
• Any other clinically significant medical, psychiatric and/or social reason as determined by the investigator.

This is a double-blind study so neither investigator and site staff, nor the subject know which treatment has been assigned.