To assess the effects of dietary vasoactive amines in the aetiology of childhood migraine, 39 children were randomly allocated to either a high fibre diet low in these substances or a high fibre diet alone. Both groups of children showed a significant decrease in the number of headaches and there was no significant difference between the two groups. Dietary vasoactive amines have not been shown in this study to influence childhood migraine. The improvement seen in both groups emphasises the need for a control diet in studies designed to show that dietary manipulation improves disease.