Early studies by this group emphasized the role of food in health and disease . Patients were usually asked to keep a diary noting their eating' habits, any symptoms and often also their pulse rate before and after meals. Foods eaten daily are most commonly suspected of being the causes of health problems. These foods comprise such staples as egg, wheat, potatoes, cow's milk, oranges, beef, peas, beans, sugar, tea and coffee. This procedure has bean found to be more satisfactory after a fast of a few days.
Alternative approaches involve testing food extracts in the skin and under the tongue ' .
Some laboratory techniques, such as those that involve the taking of bleed samples, are also available but they require further refinement. When problem substances are identified they are eliminated or the patient's exposures are controlled. Usually for foods, a diversified, rotational diet comprising a minimum number of items at each meal is recommended. The attached program of the 1975 meeting of the Society for Clinical Ecology, to which a particular group of the practitioners working in this field belong, illustrates the breadth and scope of the concepts and techniques that are applied today. Poisoning is commoner than is generally recognized since the effects are usually disguised and therefore often be unnoticed.