Infection with the gastric bacterium Helicobacter pylori provides reliable protection against allergy-induced asthma, immunologists from the University of Zurich have demonstrated in an animal model together with allergy specialists from the University Medical Center of the Johannes Gutenberg University Mainz. Their results published in the Journal of Clinical Investigation confirm the hypothesis recently put forward that the dramatic increase in allergic diseases in industrial societies is linked to the rapid disappearance of specific micro-organisms that populate the human body.