Infant Colic

The goal of this clinical trial is to evaluate whether daily probiotic supplementation with Bifidobacterium bifidum (Bifipral® drops) can reduce crying time in formula-fed infants aged 5 months or younger diagnosed with infant colic (according to Rome IV criteria), with or without concomitant atopic dermatitis. The main questions it aims to answer are: * Does daily administration of B. bifidum for 8 weeks achieve at least a 50% reduction in average daily crying duration compared to placebo? * Does B. bifidum supplementation improve secondary outcomes, including crying frequency, sleep quality, bowel movement frequency, stool consistency, fecal microbiota composition, short-chain fatty acid (SCFA) levels, and SCORAD score in infants with atopic dermatitis? Researchers will compare formula-fed infants receiving Bifipral® drops (containing B. bifidum strains BFP19® and BFP29®) to a comparison group receiving an indistinguishable placebo to see if the probiotic safely improves colic symptoms and gut microbiota balance. Participants will be asked to: * Complete a 7-day observational run-in period to confirm eligibility and record baseline symptoms in a daily diary. * Administer 5 drops daily of the study product (probiotic or placebo) for 8 weeks. * Complete daily diaries tracking crying duration/frequency, sleep parameters, and bowel habits. * Attend 3 clinical visits (Baseline, Week 8, and a Safety Follow-up 2-4 weeks post-treatment). * Provide fecal samples at Baseline (Visit 1) and Week 8 (Visit 2) for microbiota profiling and SCFA analysis.

The goal of this clinical trial is to verify whether a food supplement is effective in treating infantile colic of infants aged between 21 days and 9 months and the colonization ability of the gut microbiota by measuring faecal relative abundance of the gut microbiota probiotic treatment species. The main outcomes are: - the mean number of crying episodes and the sleep duration - Relative abundance of the gut microbiota probiotic treatment species.