One hundred years ago, Noon [Lancet 1911;1:1572-1573], using conjunctival provocation testing (CPT), was the first to demonstrate the effectiveness of subcutaneous immunotherapy (SCIT) in grass-allergic subjects with hay fever. In this centenary year, we present data that, by use of CPT and allergen-specific IgG, replicate this observation and additionally confirm the allergen specificity of SCIT by using a double-blind design employing either grass or mite SCIT in dual grass- and mite-allergic individuals.