The number of daily regurgitation episodes and the daily volume of regurgitation will be assessed on average over the last 3 days. The frequency of regurgitations away from meals and of continuous regurgitations of small volumes after feeding will be assessed on average over the last 3 days via a 4-point scale [Never; Rarely; Often; Always].

The regurgitation severity will be assessed using the adapted Vandenplas regurgitation score (from 0 to 6 being the worst) (Vandenplas et al., 1994) over the last 3 days preceding each visit.

If the infant is not constipated at inclusion and during the study, the average main stool consistency will be assessed based on the BITSS scale (Brussels Infant and Toddler Stool Scale) as well as the daily average number of stools over the last 3 days.

The BITTS scale is a reliable instrument to assess stools of non-toilet trained children. It consists of 7 color photographs of diapers containing stools from infants and toddlers categorized as Hard, Formed, Loose, or Watery (Huysentruyt et al., 2019).

If the infant is constipated at one visit during the study, the total number of each stool consistency will be assessed for the next visit based on the BITSS scale over the last 7 days. The total number of stools over the last 7 days will be calculated.

If the infant is constipated at one visit during the study, the frequency of defecation pain will be assessed for the next visit based on a 3-point scale (No; Yes, only 1 time; Yes, >1 time) over the last 7 days.

Colic will be assessed through unexplained crying duration and fussing/irritability duration on average over the last 3 days and reported based on a 4-point scale (< 1h; 1h-2h; 2h-3h; > 3h).

Gas/flatulence severity will be assessed on average over the last 3 days using a visual analog scale (from 0=No symptom to 10=Very severe symptoms).

Abdominal distension is defined as a swollen, tense and hard to the touch stomach. Its severity will be assessed on average over the last 3 days using a visual analog scale (from 0=No symptom to 10=Very severe symptoms).

Evolution of Gastrointestinal and Gastroesophageal Reflux (GIGER) scale total score (from 0 to 180) and 3 subscores (subscore 1: from 0 to 75; subscore 2: from 0 to 65; subscore 3: from 0 to 40) from baseline. The higher the GIGER is, the worst the symptoms are.

The investigator will evaluate the evolution of each FGID (i.e. regurgitations, constipation, colic) using a 4-point scale (Improvement; Worsening; No evolution; Not applicable) over the past period.

The number of bottles at night will be recorded on average over the last 3 days.

The average sleep duration will be reported over the last 3 days and sleep quality will be assessed using a visual analog scale (from 0= Difficult to fall asleep, frequent awakenings to 10= Easy and quick falling asleep, no awakenings without obvious cause).

Parents will complete the QUALIN questionnaire (score from -68 to +68) (Manificat et al., 2000) over the last week.

Weight will be expressed in kg and in z scores according to the World Health Organization (WHO) Child Growth Standards.

Height will be expressed in cm and in z scores according to the WHO Child Growth Standards.

Head circumference will be expressed in cm and in z scores according to the WHO Child Growth Standards.

BMI will be expressed in value and z scores according to the WHO Child Growth Standards.

Any untoward medical reaction occuring from the signatture of the consent until the end of the participant's participation

Parents' satisfaction will be assessed on the product use and acceptability using a 5-point Likert scale and more specifically on the evolution of each FGID (i.e. regurgitations, constipation, colic) using a 4-point scale (Improvement; Worsening; No evolution; Not applicable) over the past period.