It is widely known that there might occur three different responses to the administration of ASA or NSAID to patients with bronchial asthma-bronchoconstriction, bronchodilatation or lack of bronchopulmonary action. Nevertheless, the beneficial effect of SAID has been confirmed in patients who are both nonallergic and cortico-dependent asthmatics. Our hypothesis is that in these specific cases the arachidonic acid metabolism is diverted towards cyclo-oxygenase products and that this metabolic diversion leads to an increased production of bronchoconstriction prostaglandins. The administration of NSAID inhibits the cyclo-oxygenase suppressing the enhanced basal production of these bronchoconstrictors and relieving the bronchospasm. The suspected abnormality in arachidonic acid metabolism would be restricted to the respiratory system.