Carraro et al. measured asymmetric dimethylarginine (ADMA) in the exhaled breath condensate (EBC) obtained from children with asthma and from healthy subjects. The authors demonstrated higher levels of ADMA in EBC of asthmatics compared to controls. ADMA levels in EBC did not correlate with serum levels, lung function parameters, and fractional exhaled nitric oxide. ADMA levels in EBC did not significantly differ between asthmatic patients regularly treated with inhaled steroids and those who were steroid naïve. Further studies are necessary in order to evaluate the role of this biomarker in the characterization of phenotypes of severe bronchial asthma.