Intolerance to lactose and cow's milk protein was prospectively evaluated in 56 infants with apparent colic. A complete blood cell count, sedimentation rate, test for quantitative IgE level, radioallergosorbent test (performed in 15 patients), and at least three stool examinations for pH, presence of reducing substances, and occult blood were performed in 56 infants (46, appropriate size for gestational age; ten, small for gestational age) and results were within normal limits for age. This study suggests that tolerance to lactose and cow's milk protein does not have a significant role in infantile colic.
Liebman WM. Infantile ColicAssociation With Lactose and Milk Intolerance. JAMA. 1981;245(7):732-733. doi:10.1001/jama.1981.03310320054027