This is a randomized, single-blind, placebo-controlled study to evaluate the efficacy of the dietary supplement BioAmicus Complete (oral drops; a mixture of 10 strains of lacto- and bifidobacteria) in managing functional gastrointestinal disorders and cutaneous symptoms of food allergy in infants during the first months of life.

The aim of the study is to assess clinical effects of BioAmicus Complete drops on the symptoms of infantile colic, constipation, diarrhea, gastroesophageal reflux, atopic dermatitis/eczema in full-term newborns during the first months of life.

A prospective study comparing two treatment groups:

Group 1 (treatment group) - 70 infants. Group 2 (control group) - 70 infants, placebo. The study drug will be taken in 1 time per day within 25 days. Allowed symptomatic therapy includes defoamers (simethicone-based preparations), carminative preparations (dill water (fenhel)), etc.

Inclusion Criteria:

• The child's parents/guardians speak Russian, have been informed about the study's purpose, understand its essence, are aware of their rights, and have signed the informed consent form.
• Diarrhea or constipation accompanied by colic and/or regurgitation (gastroesophageal reflux, GER).
• Cutaneous manifestations of food allergy.
• The child was born at term or preterm, but not before the 7th month of gestation.
• Age at the time of parental informed consent: from 1 month to 4 months and 28 days.
• The child is on breastfeeding, formula feeding, or mixed feeding.
• The child has no other health conditions that would require a specialized diet.
• The parents/guardians are able and willing to regularly complete the proposed observation diary form.

Exclusion Criteria:

• The child has a congenital pathology or any other conditions/diseases/clinical manifestations that may interfere with participation in the study.
• Use of lactase supplements.
• Use of other probiotic products, antibiotics, enteral antiseptics, antifungal, or antiprotozoal medications.
• The child was born preterm (before the 7th month of gestation).