Care Co-Lactase drops break down the lactose in breast and formula milk before feeding to your baby. Lactose is a complex sugar found in milk, dairy products, infant formulas and breast milk. Lactase is the enzyme usually produced by our bodies to break down lactose into more simple sugars so our bodies can absorb it. The immature digestive system of babies can have trouble breaking down the lactose in milk into more simple sugars. Your doctor or health visitor can tell you more about how this may affect your baby.