20 out of 36 children (aged two to eight years) with atopic eczema completed a twelve-week, double-blind, controlled, crossover trial of an egg and cows' milk exclusion diet. During the first and third four-week periods, patients on an egg and cows' milk exclusion diet received a soya-based milk substitute (trial period) or an egg and cows' milk preparation (control period). Response was assessed in terms of eczema activity, number of areas affected, pruritus, sleeplessness, and antihistamine usage while on the two diets. During the middle period patients resumed their normal diet to minimise any carry-over effect. 14 patients responded more favourably to the antigen-avoidance diet than to the control diet, whereas only 1 responded more favourably to the control diet than the trial diet. Patients experienced more benefit during the first diet period than the second, whatever the nature of the diet. There was no correlation between a positive prick test to egg and cows' milk antigen and response to the trial diet.