There are many causes for colic, some of them are overfeeding, underfeeding, infrequent burping, stress, food allergies, imbalance of healthy bacteria in the digestive system. But one of the main causes for colic in your baby is because they have a digestive system that isn't fully developed. A baby's digestive system is still just learning to function for the first two years. Muscles that support digestion have not developed the proper rhythm (peristalsis) for moving food efficiently thought the digestive tract. Additionally, new born babies lack the needed quantity of bacterial flora (probiotics) that develop over time to aid digestion and complement the work performed by enzymes secreted in the digestive tract.