ZusammenfassungBackground: As a vegan diet is per definition a plant-based diet, consumers rely on plant protein sources in order to substitute animal proteins. Plant protein sources commonly used in this context are the following: cereals, like wheat (Triticum aestivum, Triticum durum), oat flakes; pseudo cereals like quinoa; nuts and oil seeds like cashew (Anacardium occidentale), hazelnut (Corylus avellana), walnut (Juglans regia); seeds like psyllium seeds (Plantago ovata), sesame (Sesamum indicum), and chia seed (Salvia hispanica).Methods: In order to assess the allergy risk posed by vegan diet, a literature search focusing on the composition of this particular diet and whether the respective foods are potentially allergenic was performed.Results: At first glance, it is evident for allergologists that these protein sources are well-known allergen sources. Particularly nuts and legumes harbour storage proteins, oleosins, and lipid trans- fer proteins that as such are associated with severe allergic reactions to food. In addition, there is increasing evidence that the simultaneous consumption of several of these foods may produce a summation effect where many single allergens of high allergenic potential sum up, thereby inducing anaphylaxis. Furthermore, food processing - or the lack of it - puts patients with pollen-associated food allergy at risk to react to some of the plant foods used in vegan diets.Conclusion: Therefore, individuals with a history of atopy should be educated regarding the allergy risk of a vegan diet.Cite this as Jappe U. Vegan diet - alternative protein sources as potential allergy risk. Allergo J Int 2023;32:251-7https://doi.org/10.1007/s40629-023-00248-7