Foods with advisory labeling (eg, "may contain") are increasingly prevalent. Consumers with food allergies might ignore advisory labeling advice. We sought to determine whether consumers with food allergy heeded advisory labels and whether products with advisory labels contained detectable peanut allergen. Surveys (n = 625 in 2003 and n = 645 in 2006) were conducted at Food Allergy & Anaphylaxis Network patient conferences. Food products bearing advisory statements regarding peanuts were analyzed for the presence of peanut. Consumers were less likely to heed advisory labeling in 2006 (75%) compared with in 2003 (85%, P < .01); behavior varied significantly according to the form of the statement. Peanut protein was detected in 10% (20/200) of total food products bearing advisory statements, although clinically significant levels of peanut (>1 mg of peanut or >0.25 mg of peanut protein) were detected in only 13 of 200 such products. Consumers with food allergy are increasingly ignoring advisory labeling. Because food products with advisory labeling do contain detectable levels of peanuts, a risk exists to consumers choosing to eat such foods. The format of the labeling statement did not influence the likelihood of finding detectable peanut, except for products listing peanuts as a minor ingredient, but did influence the choices of consumers with food allergy. Allergic patients are taking risks by increasingly disregarding advisory labeling.