There is a general consensus that the mortality rates for asthma in much of the developed world have been increasing for the past 10-15 years. This has occurred despite an improved information base regarding diagnosis and management as well as the development of novel and more effective therapeutic modalities. Several explanations have been proposed for this increase, including a statistical artifact based on a change in the coding criteria for asthma from the International Classification of Diseases Version 8 (ICD-8) to ICD-9, worsened pollution, delays in seeking medical help, behavioral changes, deficits in asthma education of both patients and primary care providers, toxicity of beta agonists, and noncompliance with medications. We suggest that although all of these are potential etiological factors, there may exist still another major etiological risk. There have been dramatic changes in our eating habits and food preparation. In general, we eat less total calories, more meals outside the home, and more refined or prepared foods. With the emphasis on reducing the intake of saturated fats and cholesterol, we eat more polyunsaturated fats both by choice and secondary to manufacturers' attempts to improve the appeal of foods to health-conscious government and the public. The drive to remove animal fats and cholesterol from our diet has resulted in the replacement of animal fats with vegetable oil in food manufacture, fast-food frying, and even home preparation. One result of these dietary habits has been a doubling from 8 to 15% of the percentage of the polyunsaturated linoleic acid in body fat. We postulate that this, and other nutritional changes, will render asthma a more difficult syndrome to manage and will contribute adversely to the inflammatory abnormalities in airways.