The subject was a common-migraine sufferer for many years. He kept detailed records regarding the frequency of his headaches and medication taken. An aspirin-induced gastrointestinal bleed caused him to begin a bland oligoantigenic diet. He became headache-free shortly thereafter. Single food challenges, done carefully and deliberately, revealed sensitivities to banana, citrus, and cheese, all foods containing potent vasoactive amines. The year prior to his serendipitous discovery, the subject had headache on 326 days and took 1316 aspirin tablets. The year following it, in which he eliminated offending foods, he had headache on 8 days and took 16 tablets. Seven years of headache data are presented. Delayed reactions to foods, and multiple food sensitivities, may pose diagnostic problems. Headaches can occur up to 72 hours following ingestion of provoking foods. Oligoantigenic diets and single food challenges utilizing enough time so as to recognize delayed reactions are useful in detecting food sensitivities.