This supplement has been clinically tested in over 145 studies and shown to be one of the safest and most effective probiotics for infants. A single 5 drop dose contains 100 million lactobacillus reuteri. Loved by paediatricians worldwide, this probiotic helps your baby maintain a healthy balance of bacteria in their gut, promoting growth of good bacteria after a course of antibiotics and providing fuel for digestive tract cells. In turn, this nourishes your baby's immune system, as 70% of their immune system resides in their gut. Always buy probiotics from a reputable seller. At IMI, we are rigorous in our temperature and humidity control, ensuring the good bacteria are live and effective when they reach you.