76 selected overactive children were treated with an oligoantigenic diet, 62 improved, and a normal range of behaviour was achieved in 21 of these. Other symptoms, such as headaches, abdominal pain, and fits, also often improved. 28 of the children who improved completed a double-blind, crossover, placebo-controlled trial in which foods thought to provoke symptoms were reintroduced. Symptoms returned or were exacerbated much more often when patients were on active material than on placebo. 48 foods were incriminated. Artificial colorants and preservatives were the commonest provoking substances, but no child was sensitive to these alone.