Lactobacillus Reuteri Versus Placebo in the Treatment and Prevention of Infantile Colic

The purpose of this study is: * to study the intestinal microflora of colicky infants before and after L. reuteri or placebo administration, evaluating the effect of Lactobacillus reuteri on the growth of the main intestinal microbiota (coliforms, Clostridium butyricum, Lactobacilli, Bifidobacteria) with fluorescent in situ hybridization (FISH) technique or with Real-Time PCR Taqman; Further, the global intestinal microflora composition, using large-scale DNA sequencing of 16S rRNA genes ( 454-pyrosequencing technique. * to evaluate the improvement of colicky symptoms by the oral administration of Lactobacillus reuteri (primary outcome: reduction of the daily average crying time from baseline to the end of the treatment period, to less than 3 hours a day, the cut-off proposed by Wessel; secondary outcome: number of responders versus non-responders in each group at the end of the treatment). * to evaluate fecal calprotectin values at the beginning and at the end of the study. BÜHLMANN Quantum Blue® Calprotectin High Range (Schönenbuch, Switzerland). A quantitative immunoassay. * to evaluate Th17/Treg balance at time 0 and t 30 ( days) investigating mRNA FOXP3 and RORγ in peripheral blood using RT-PCR Real Time Taqman. * the measurement of the expression level of CC-chemokine receptor 7 messenger RNA using the real-time TaqMan reverse transcription polymerase chain reaction method. * the measurement of expression of interleukin 10 (IL-10) messenger RNA using the real-time TaqMan reverse transcription polymerase chain reaction method. * Parental satisfaction at the end of the study period ( 30 day ) with a numerc scale from 1 to 10.