This study is a randomized, double-blind, placebo-controlled, two-armed, parallel-group study in healthy children aged 2-6 years. The study will investigate the effect of daily intake of a probiotic on Upper Respiratory Tract Infections (URTI) during a 16-week intervention.

Inclusion Criteria:

1. Children aged 2-6 years, both inclusive, at the time of informed consent
2. No URTI at the time of inclusion as assessed by a GP
3. Attending day-care with at least 10 children or primary school with at least 10 children in the class for at least 20 hours a week
4. Generally healthy as determined by a GP
5. Guardian consents to participate in the study and to comply with all its procedures

Exclusion Criteria:

1. Any known concomitant chronic infections, chronic systemic diseases, autoimmune diseases (e.g. asthma), immunodeficiency, metabolic diseases, chronic respiratory tract diseases including respiratory allergies and cystic fibrosis, congenital cardiac defects.
2. Suspected or challenge-proved food allergy
3. Use of any prescribed immune suppressive medications at enrolment
4. Use of oral or IV antibiotics in the 1 month before randomisation
5. Not willing to exclude pre/pro/synbiotics during the study
6. Intake of Echinacea, high dose vitamins or Zinc four weeks before and during the study period.
7. Language limitations regarding interviews or questionnaires
8. Participation in other clinical studies in the last 2 months
9. Planning extensive travel (for >1 month) during the duration of the study