Two cases of presumed food allergy are presented in infants who showed acute constitutional reactions following ingestion of commonly used foods; squash in one and sweet potatoes in the other. The manifestations of the reaction were delayed, taking place approximately 90 minutes after ingestion of the offending foods. Skin tests by the passive transfer method failed to reveal any sensitizing antibody in the patients' circulating blood. It is pointed out that a more reliable method to demonstrate antigen-antibody mechanism is needed in the study of food allergy.