The major birch allergen Betulae verrucosa 1, (Bet v 1), belongs to the proteinase 10 (PR-10) family of panallergens that are common to many fruits, nuts and vegetables. A high proportion of birch-sensitised individuals experience oral symptoms upon consumption of such foods. This has been termed ‘oral allergy syndrome (OAS),’ or ‘pollen-food syndrome.’ Birch pollen specific immunotherapy (BP-SIT) can successfully treat birchsensitive rhinitis; it has been postulated that BP-SIT might also reduce oral allergy symptoms. Previous studies have been small and contradictory, using differing methodology and primary outcome measures. We designed a placebo controlled, double blind, randomised study aiming to establish definitively whether BP-SIT can effectively treat the pollen-food syndrome; outcome measures include open and double blind placebo controlled food challenges (DBPCFC) after one and two years of treatment. To date 22 patients have been enrolled, 18 have undergone assessment at one year and ten at two years. Four patients are due to attend for final followup in Autumn 2015. Eight patients have dropped out. Of the ten who have completed the study: nine have an increased tolerance to fresh apple as evaluated by open challenge. When assessed with DBPCFC, six patients tolerated larger quantities of fresh apple at two years compared to baseline. However, a total of eight patients were noted to have an apple threshold of 100g or more at baseline, despite reacting to only 20g during screening. The clinical trial is on going and remains blinded; it is therefore impossible to draw any firm conclusions regarding the efficacy of BP-SIT to treat OAS at this time.