New food allergies caused by sensitization to non-food allergens are recently emerging and are getting known in clinical practice. As a result, the Japanese guideline for food allergy 2021 updates information on food allergies caused by non-food antigen sensitization in a separate chapter (chapter 14). Information on protein families involved in cross-reactivity has been included in Chapter 14-1. In Chapter 14-3, pork-cat syndrome and bird-egg syndrome were newly discussed as food allergies, which pet owners potentially create. In Chapter 14-4, descriptions of animal meat allergy caused by α-Gal after the tick bite and natto allergy caused by poly gamma glutamic acid after jellyfish sting were included as food allergies associated with animal bites. This review concentrates on the theoretical underpinnings and clinical characteristics of food allergies caused by sensitization to non-food allergens.