In a 23-year-old man with recurrent nephrotic syndrome the responsibility of pollens from graminaceous plants could be demonstrated on clinical grounds (seasonal character of the syndrome, onset of proteinuria 24 hours after injection of the allergens) and by laboratory tests (increase in IgE levels, presence of specific IgE's, positive basophil degranulation test). There is ample evidence that some cases of nephrotic syndrome may be of allergic origin. A systematic search for air and food allergens should be considered, since the discovery of these allergens may lead to an aetiological treatment.