Evaluating the Effect of Probiotic Limosilactobacillus Reuteri (L. Reuteri) on Crying and Fussing Time in Infants With Colic

1. Aged between 3-12 weeks at screening.
2. Gestational age 37+0 weeks - 42+0 weeks at birth.
3. Birth weight appropriate for gestational age (AGA - weight between 10th and 90th percentile) or Large for Gestational Age (LGA - weight above the 90th percentile) determined using WHO Weight-for Age percentile guides.
4. Parents/caregivers/legal guardians are >18 years.
5. Exclusively or predominantly breastfed infants (> 50 % breast fed).
6. Willing to maintain current feeding patterns (not change formula/not change ratio of formula:breast milk etc.).
7. Readiness and the opportunity for parents/caregivers/legal guardians to fill out a study diary, questionnaires.
8. Infantile colic diagnosed according to Rome IV criteria (face-to-face consult with a physician, parents/caregivers/legal guardians must report that their infant has cried or fussed for 3 or more hours per day, during 3 or more days in the preceding week). At Visit 2, this will be confirmed by Baby's Day Diary®, at least one 24-hour period should show 3 or more hours of crying/fussing time.
9. Parents/caregivers/legal guardians with ability to understand and comply with the requirements of the study, as judged by the Investigator.
10. Parents/caregivers/legal guardians willing and able to give informed consent for their and their infant's participation in the study.
11. The mother of the infant must be willing to attend Visit 2 (Day 0), Visit 3 (Day 8), and Visit 4 (Day 22).
12. Infant is considered healthy, in the opinion of the investigator following physical exam.

Exclusion Criteria:

1. Infants with severe gastroesophageal reflux (throwing up or spitting up more than a teaspoon of milk > 8 times daily, projectile, bilious or bloody emesis).
2. Infants with failure to thrive, intrauterine growth retardation, haematochezia (blood in the stools), diarrhoea (watery stools that takes the shape of a container > 12x in breastfed and >5 in partially breastfed infants daily), or fever (38.0 degrees), as reported by parents/caregivers/ legal guardians.
3. Infants with congenital heart disease, immunodeficiency, asplenia, cancer, cystic fibrosis, and those with liver disease.
4. Infants with reported exposure to probiotics in the 7 days prior to Screening Visit (V1) and throughout the study period.
5. Infants with reported exposure to oral and/or systemic antibiotics in the 7 days prior to Screening Visit (V1) and throughout the study period.
6. Infants with reported exposure to medications, therapies, or products with the aim to relieve infantile colic including proton pump inhibitors in the 7 days prior to Screening Visit (V1) and throughout the study period.