The role of food intolerance in asthma is well recognized, and where food avoidance measures are instituted considerable improvement in asthma symptoms and in reduction in drug therapy and hospital admissions can result. These benefits may have a greater impact in those patients with greater symptoms. However, the promise of such benefits should not result in an approach which ignores inhaled drug therapy, or in a dietary regime which is inappropriate in the face of mild symptoms. Whilst sub-optimal intake of dietary nutrients is also a recently recognized potential risk factor for asthma, available data are insufficient to implicate any as casual. A number of studies have sought to establish the role of the antioxidant vitamins, A, C and E and selenium, yet others of the elements sodium and magnesium. Sub-optimal nutrient intake may enhance asthmatic inflammation, consequently contributing to bronchial hyperreactivity. Prospective studies of supplementation therapy are needed to confirm this.