This article discusses practical issues in diagnosing cow's milk protein allergy and intolerance in children. It notes that these conditions are often difficult to distinguish based on clinical features alone. Cow's milk protein allergy is an immunoglobulin E-mediated reaction to proteins in cow's milk, while intolerance involves non-immunological mechanisms. The article provides guidance on differentiating the two and indicates when referral to a pediatric gastroenterologist is appropriate. It also reviews prevalence rates and common clinical presentations of cow's milk protein allergy and intolerance in infants and children.