To understand the clinical features of gastrointestinal cow's milk allergy in children, and to assess the importance of cow's milk challenge.An analysis was performed on the clinical manifestations and the challenge results of 50 children who received cow's milk challenges after admission to the department of gastroenterology, Children' s Hospital of Zhejiang University School of Medicine from January,2009 to December, 2012. The value of immunoglobulin E antibody was also analyzed among the 50 children, 25 cases were male and the other 25 were female. The youngest subject was 1. 6 months old, and the oldest was 20 months, most of the cases were younger than 6 months (36 cases).(1) Diarrhea (27 cases, 54%) and hematochezia (25 cases, 50%) were the most common clinical features, vomiting, hematemesis and abdominal distention were rare. (2) Cow's milk challenges failed in 58% of the cases, 90% of whom showed delayed allergy. Diarrhea (19 cases, 73%) was the major later presentation, whereas the immediate hypersensitivity showed angio-edema, gastrointestinal symptom and rash. (3) The neutrophil count ((3.8 ± 2.8) x 10(9)/L vs. (2.5 ± 1.3) x 10(9)/L) was higher after challenge among children who failed the challenge. The change in the count of blood cell, neutrophil and platelet was studied, however, there were no statistical differences between the challenge-failed children and the passed ones. (4) Forty-seven cases had milk specific immunoglobulin E antibody test, and 5 showed positive results, 4 of whom were seen among the challenge-failed children.Diarrhea and hematochezia was the most common clinical manifestation, and cow's milk protein induced proctocolitis was the most common disease in practice. It is important and necessary to perform cow's milk challenge.