Some babies have long crying spells and cannot be easily comforted. Excessive crying or fussiness is sometimes called colic and may be due to a sensitivity to the protein in the formula. Other symptoms such as severe diarrhea, rashes and even sleeping problems can be caused by protein sensitivity. Similac Alimentum is a trusted alternative to both milk based and soy based Similac Formula. If the babies digestive system is especially sensitive and requires an extra gentle formula, ask the doctor about Similac Alimentum. This formula from Similac is easy for sensitive babies to digest because its protein is broken down into tiny pieces to virtually eliminate allergic reations in most babies who are allergic to cows milk protein.