Because food allergy treatment is basically avoidance of the offending food(s), identification of the latter becomes the cornerstone for management. At present, the elimination-challenge test is the most definitive procedure for verification of a cause-and-effect relationship between a particular food and a certain reaction, allergic or not. The oral challenge test is most reliable when conducted in a double-blind, placebo-controlled manner. In routine clinical practice, however, single-blind testing is satisfactory in most cases. Open challenge testing might be acceptable in young children or for screening the least suspected foods. It would be prudent to avoid the test, in any of its forms, in instances where a specific food caused a life-threatening reaction. Caution needs to be practiced in planning, conducting, and interpreting the results of challenge tests. Difficulties may be encountered in disguising the test food, choosing a placebo, reproducing the natural exposure, incorporation of possible associated factors, and avoiding any bias on the patient's or observer's part.