This study will evaluate the safety and tolerability of Lactobacillus reuteri in healthy infants with colic. Patients will be randomized to receive either L. reuteri at one dose orally for a total of 42 doses. The doses will be 5x108 (5 drops) during a satisfactory assessment of safety and tolerability. The time on study treatment is 6 months, and the target sample size is 45 healthy infants.
Secondly, the investigators aim to gather evidence supporting hypothesis of safety and tolerability of Lactobacillus reuteri by administering a physical examination and testing of complete blood count, liver tests, and serum electrolytes over a forty-two day period.