2-Aminoacetophenone can be detected in the breath of Pseudomonas aeruginosa colonized cystic fibrosis patients; however, low levels were also detected in a small proportion of healthy subjects. It was hypothesized that food, beverages, cosmetics or medications could be a source of contamination of 2-aminoacetophenone in breath. To determine the potential confounding of these products on 2-aminoacetophenone breath analysis, screening for this volatile was performed in the laboratory by gas chromatography/mass spectrometry and a food challenge study carried out. 2-Aminoacetophenone was detected in four of the 78 samples tested in vitro: corn chips and canned tuna (high pmol mol(-1)) and egg white and one of the three beers (low pmol mol(-1)). No 2-aminoacetophenone was detected in the CF medication or cosmetics tested. Twenty-eight out of 30 environmental air samples were negative for 2-aminoacetophenone (below 50 pmol mol(-1)). A challenge study with ten healthy subjects was performed to determine if 2-aminoacetophenone from corn chips was detectable on the breath after consumption. Analysis of mixed breath samples reported that the levels of 2-aminoacetophenone were immediately elevated after corn chip consumption, but after 2 h the level of 2-aminoacetophenone had reduced back to the 'baseline' for each subject.