In 1994, Professor Bengt Björksten from the University of Linköping in Sweden was a visiting professor at the University of Tartu in Estonia. Professor Björksten noticed that very few Estonian children suffered from allergies, whereas the incidence of allergies among Swedish children was much higher. This motivated Professor Björksten to initiate a joint research project between doctors in the Department of Pediatrics at the University of Linköping with Professor Marika Mikelsaar and the Department of Microbiology at the University of Tartu.¹ Stool samples were collected from the Swedish and Estonian children to assess if differences in the bacteria in their gut microbiome might provide insights regarding the incidence of allergies. Significant differences were found in the intestinal bacteria of children who develop allergies compared to children who remain allergy free.